CYFIP1 governs the development of cortical axons by modulating calcium availability

Nefiracetam targets both L- and N-type calcium channels.

“whereas Nefiracetam has a broader effect, targeting both L- and N-type calcium channels.”

• cites [74] Trujillo, C. A. et al. Pharmacological reversal of synaptic and network pathology in human MECP2‐KO neurons and cortical organoids. EMBO Mol. Med. 13, e12523 (2021). sourceCould not verify

  The Results section reports that nefiracetam increased calcium-transient frequency in MECP2-mosaic neurospheres, but it does not identify the calcium channels involved. Searches for L-type and N-type calcium channels found no passage in our copy stating that nefiracetam targets either channel type; page numbers are unavailable. (LLM, conf=0.74)

  Experimental — accuracy not yet measured

Published nELAVL CLIP-seq data from human brain found that hCACNA1C, hCACNA1E and hCACNA1I are targets of nELAVL proteins.

“a published nELAVL CLIP-seq experiment from human brain found that hCACNA1C, hCACNA1E and hCACNA1I are targets of nELAVL proteins66”

• cites [66] Scheckel, C. et al. Regulatory consequences of neuronal ELAV-like protein binding to coding and non-coding RNAs in human brain. eLife 5, e10421 (2016). sourcePartly supported

  The Results section, “Identification of nELAVL targets in human brain” (page unavailable), confirms that the authors performed CLIP on human brain samples and identified nELAVL RNA-binding sites. The passages in our copy do not identify CACNA1C, CACNA1E, or CACNA1I as targets; searches for those gene names found no matching passage. Thus the experiment is supported, but the specific target list is not verified. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

CYFIP1 regulation of calcium channel subunits compromises intracellular calcium levels, resulting in delayed axonal development.

“These findings support our model in which CYFIP1 regulation of calcium channel subunits compromise intracellular calcium levels, resulting in delayed axonal development10,84,85 (Fig. 7).”

• cites [10] Purcell, S. M. et al. A polygenic burden of rare disruptive mutations in schizophrenia. Nature 506, 185–190 (2014). sourcePartly supported

  The Extended Data table lists a disruptive CYFIP1 variant, and the ‘ARC, PSD-95 and calcium ion channel genes’ section reports mutations in calcium-channel subunits. The Discussion proposes altered calcium-dependent signaling as a possibility. Neither passage shows that CYFIP1 regulates those subunits, changes intracellular calcium levels, or delays axonal development; those links are the citing authors’ model, not findings established by this source. (LLM, conf=0.78)

  Experimental — accuracy not yet measured
• cites [84] Ciccolini, F. et al. Local and Global Spontaneous Calcium Events Regulate Neurite Outgrowth and Onset of GABAergic Phenotype during Neural Precursor Differentiation. J. Neurosci. 23, 103–111 (2003). sourcePartly supported

  The Results section (page not specified in our copy) reports that low-calcium conditions significantly shortened neurites in differentiating neural precursors. That supports the calcium–outgrowth link, but the paper does not establish that CYFIP1 regulates calcium-channel subunits or that this mechanism delays axonal development. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [85] Arjun McKinney, A., Petrova, R. & Panagiotakos, G. Calcium and activity-dependent signaling in the developing cerebral cortex. Development 149, dev198853 (2022). sourcePartly supported

  The review’s “Mechanisms regulating intracellular calcium signaling” section explains that calcium-channel subunits regulate calcium entry. Its “Differentiation” section links intracellular calcium signaling to axonal pathfinding and neuronal activity to callosal axon outgrowth. It does not identify CYFIP1 as a regulator of those subunits or establish the proposed chain from CYFIP1 to altered calcium levels and delayed axonal development; the citing sentence labels that chain as the authors’ model. Page numbers were not available in our copy. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

Abnormalities in the corpus callosum and interhemispheric connectivity are linked to many neurodevelopmental disorders, including ASD and SCZ.

“a wealth of evidence links abnormalities in the corpus callosum and interhemispheric connectivity (driven by callosal projection neurons) to many neurodevelopmental disorders, among them ASD and SCZ2,3,111,112.”

• cites [2] Heinsfeld, A. S., Franco, A. R., Craddock, R. C., Buchweitz, A. & Meneguzzi, F. Identification of autism spectrum disorder using deep learning and the ABIDE dataset. Neuroimage Clin. 17, 16–23 (2017). sourcePartly supported

  The paper’s “Neural patterns: connectivity in the autistic brain” section reports disrupted anterior–posterior connectivity in ASD and links that theory to corpus callosum morphometry (page unavailable). It does not establish abnormal interhemispheric connectivity, a role for callosal projection neurons, or a link to schizophrenia or neurodevelopmental disorders generally. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [3] Hu, M.-L. et al. A Review of the Functional and Anatomical Default Mode Network in Schizophrenia. Neurosci. Bull. 33, 73–84 (2017). sourcePartly supported

  The section “Functional Connectivity in the DMN in Schizophrenia” reports abnormal connectivity in schizophrenia, supporting that part of the claim. The paper does not link those findings to corpus callosum abnormalities or interhemispheric connectivity; the retrieved mention of autism is a reference entry, not evidence for the claimed link across ASD and other disorders. No page numbers are available in our copy. (LLM, conf=0.83)

  Experimental — accuracy not yet measured
• cites [111] Urchs, S. G. W. et al. Functional connectivity subtypes associate robustly with ASD diagnosis. eLife 11, e56257 (2022). sourcePartly supported

  The Results section reports functional-connectivity alterations associated with ASD diagnosis. But the passages do not identify those alterations as interhemispheric or callosal, and the paper's Discussion (Limitations) says its analysis focused on ASD rather than other disorders. The source therefore does not support the corpus-callosum or schizophrenia parts of the claim. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [112] Fenlon, L. R. & Richards, L. J. Contralateral targeting of the corpus callosum in normal and pathological brain function. Trends Neurosci. 38, 264–272 (2015). sourceNot checked — no full text of the source

mMap1b mRNA is significantly associated with CYFIP1, >1.5 fold compared to mHprt1 mRNA.

“mMap1b mRNA, an mRNA previously identified in the CYFIP1 complex21, was significantly associated with CYFIP1, >1.5 fold compared to mHprt1 mRNA”

• cites [21] Napoli, I. et al. The fragile X syndrome protein represses activity-dependent translation through CYFIP1, a new 4E-BP. Cell 134, 1042–1054 (2008). sourceSupported

Cyfip1+/- rats show extensive white matter changes, most pronounced in the corpus callosum.

“Similar observation using diffusion tensor imaging, showed extensive white matter changes in Cyfip1+/- rats, which were most pronounced in the corpus callosum32.”

• cites [32] Silva, A. I. et al. Cyfip1 haploinsufficient rats show white matter changes, myelin thinning, abnormal oligodendrocytes and behavioural inflexibility. Nat. Commun. 10, 3455 (2019). sourcePartly supported

  The Results section, “Cyfip1 haploinsufficiency disrupts white matter microstructure” (page unavailable), reports DTI-detected white matter changes in Cyfip1+/− rats. It identifies both the corpus callosum and external capsule—not the corpus callosum alone—as the sites of the most extensive changes. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

Developing Cyfip1+/- cortical neurons at DIV3 exhibit significantly reduced cytoplasmic and axoplasmic calcium concentrations compared to WT.

“We found that developing Cyfip1+/- cortical neurons at DIV 3 exhibit significantly reduced cytoplasmic and axoplasmic [Ca2+] compared to WT (Fig. 3a and S3a).”

Cyfip1-deficient cortical neurons and axons have impaired mitochondria motility.

“Additionally, Cyfip1-deficient cortical neurons and axons have reduced intracellular calcium, along with impaired mitochondria morphology, activity, and motility.”

• Also stated in: § Cyfip1+/- cortical axons display increased mitochondrial density and motility · plain

  “We found that the axons of Cyfip1+/- cortical neurons have an increased percentage of motile mitochondria compared with WT”

The growth of Cyfip1+/- axons is reduced compared with WT in vitro at DIV3-4.

“As shown in Fig. 2a, the growth of Cyfip1+/- axons was reduced compared with WT.”

At later developmental stages in vitro, the reduction in mitochondrial membrane potential is no longer observed.

“However, when evaluated at later developmental stages in vitro, this reduction was no longer observed (Fig. S3c, d).”

Cyfip1-deficient cortical neurons and axons have reduced intracellular calcium.

“Additionally, Cyfip1-deficient cortical neurons and axons have reduced intracellular calcium, along with impaired mitochondria morphology, activity, and motility.”

• Also stated in: § Intracellular Ca2+ homeostasis and mitochondrial activity are compromised in Cyfip1 deficient neurons · plain

  “We found that developing Cyfip1+/- cortical neurons at DIV 3 exhibit significantly reduced cytoplasmic and axoplasmic [Ca2+] compared to WT”

Mitochondrial density is increased in Cyfip1+/- axons compared to WT.

“We found that mitochondrial density was increased in Cyfip1+/- axons compared to WT.”

By P30, axonal arborization is comparable between WT and Cyfip1+/- mice.

“By postnatal day 30 (P30), axonal arborization was comparable between WT and Cyfip1+/- mice (Fig. S1)”

Mitochondrial density along dendrites is comparable between WT and Cyfip1+/-.

“while mitochondrial density along dendrites was comparable between the two genotypes (Fig. S2a)”

Mitochondria in Cyfip1+/- axons exhibit reduced calcium levels.

“Our results revealed that mitochondria in Cyfip1+/- axons exhibit reduced calcium levels (Fig. 3b).”

CYFIP1 binds and stabilises the mRNA of specific voltage-gated calcium channel subunits.

“Mechanistically, CYFIP1 binds and stabilises the mRNA of specific voltage-gated calcium channel subunits, explaining the decreased calcium concentration in Cyfip1+/- cells.”

• Also stated in: § CYFIP1 regulates the expression of specific calcium channel subunits by interacting with Hu proteins · hedged

  “Together, these results demonstrate that CYFIP1 regulates the mRNA and protein levels of alpha-1 subunits of CaV channels in developing cortical neurons and axons and suggest that the mechanism of regulation may be at the level of mRNA stability.”

Total mitochondrial mass is similar for WT and Cyfip1+/- cortical neurons.

“In addition, the total mitochondrial mass, measured as the mitochondrial to total DNA ratio, was similar for WT and Cyfip1+/- cortical neurons (Fig. 2c)”

Axonal growth into the contralateral cortex is reduced at P5 in Cyfip1+/- mice.

“We found that axonal growth into the contralateral cortex was reduced at P5 in Cyfip1+/- mice”

The reduction in branches in Cyfip1+/- mice is due to a decrease in both primary and secondary branches.

“The total number of branches in Cyfip1+/- mice was reduced compared to WT, due to a decrease in both primary and secondary branches”

Elevating intracellular calcium rescues delayed axonal growth in Cyfip1-deficient neurons.

“Notably, elevating intracellular calcium rescues delayed axonal growth and mitochondrial defects in Cyfip1-deficient neurons.”

• Also stated in: § Introduction · boosted

  “Notably, elevating intracellular calcium concentration was sufficient to rescue both axonal growth and mitochondrial defects in Cyfip1+/- neurons.”

Cyfip1-deficient cortical neurons and axons have impaired mitochondria morphology.

“Additionally, Cyfip1-deficient cortical neurons and axons have reduced intracellular calcium, along with impaired mitochondria morphology, activity, and motility.”

• Also stated in: § Intracellular Ca2+ homeostasis and mitochondrial activity are compromised in Cyfip1 deficient neurons · plain

  “The analysis revealed a significantly increased mitochondrial area and elongation of the major axis of mitochondria in Cyfip1+/- axons.”

In vivo, Cyfip1 heterozygosity delays callosal axon growth.

“In vivo, Cyfip1 heterozygosity delays callosal axon growth and arborization.”

• Also stated in: § Axonal development in vivo is impaired in Cyfip1+/- mice · plain

  “We found that axonal growth into the contralateral cortex was reduced at P5 in Cyfip1+/- mice”

• Also stated in: § Axonal development in vivo is impaired in Cyfip1+/- mice · hedged

  “indicating that Cyfip1 deficiency leads to a delay in axonal growth”

In vivo, Cyfip1 heterozygosity delays callosal axon arborization.

“In vivo, Cyfip1 heterozygosity delays callosal axon growth and arborization.”

• Also stated in: § Axonal development in vivo is impaired in Cyfip1+/- mice · plain

  “The total number of branches in Cyfip1+/- mice was reduced compared to WT, due to a decrease in both primary and secondary branches”

• Also stated in: § Axonal development in vivo is impaired in Cyfip1+/- mice · hedged

  “By postnatal day 30 (P30), axonal arborization was comparable between WT and Cyfip1+/- mice (Fig. S1) indicating that arborization is also slowed down.”

Mitochondrial membrane potential is reduced in axons of Cyfip1+/- DIV3 cortical neurons compared to WT.

“Our analysis revealed a reduction in mitochondrial membrane potential in both the axons (Fig. 3c) and cell bodies (Fig. S3b) of Cyfip1+/- DIV 3 cortical neurons compared to WT.”

The total number of branches in Cyfip1+/- mice is reduced compared to WT at P15.

“The total number of branches in Cyfip1+/- mice was reduced compared to WT, due to a decrease in both primary and secondary branches”

Cyfip1-deficient cortical neurons and axons have impaired mitochondria activity.

“Additionally, Cyfip1-deficient cortical neurons and axons have reduced intracellular calcium, along with impaired mitochondria morphology, activity, and motility.”

• Also stated in: § Intracellular Ca2+ homeostasis and mitochondrial activity are compromised in Cyfip1 deficient neurons · plain

  “Our analysis revealed a reduction in mitochondrial membrane potential in both the axons (Fig. 3c) and cell bodies (Fig. S3b) of Cyfip1+/- DIV 3 cortical neurons compared to WT.”

Mitochondrial transport at later developmental stages is comparable between WT and Cyfip1+/-.

“Interestingly, mitochondrial transport at later developmental stages was comparable between WT and Cyfip1+/- (Fig. S2c).”

The axons of Cyfip1+/- cortical neurons have an increased percentage of motile mitochondria compared with WT.

“We found that the axons of Cyfip1+/- cortical neurons have an increased percentage of motile mitochondria compared with WT (Fig. 2d).”

The P5 axonal growth defect in Cyfip1+/- mice is rescued by electroporation of WT Cyfip1 cDNA.

“Notably, this defect was rescued when we electroporated, together with tdTomato, the WT form of Cyfip1 (Cyfip1+/- + cDNA Cyfip1)”

Elevating intracellular calcium rescues mitochondrial defects in Cyfip1-deficient neurons.

“Notably, elevating intracellular calcium rescues delayed axonal growth and mitochondrial defects in Cyfip1-deficient neurons.”

• Also stated in: § Introduction · boosted

  “Notably, elevating intracellular calcium concentration was sufficient to rescue both axonal growth and mitochondrial defects in Cyfip1+/- neurons.”

Other mitochondrial motility parameters (forward and backward movement length, speed, and frequency of reverse direction transitions) show no significant differences between WT and Cyfip1+/-.

“Several other parameters analyzed, including forward and backward movement length, forward and backward movement speed, and the frequency of reverse direction transitions, showed no significant differences between the two genotypes (Fig. S2b).”

Mitochondrial membrane potential is reduced in cell bodies of Cyfip1+/- DIV3 cortical neurons compared to WT.

“Our analysis revealed a reduction in mitochondrial membrane potential in both the axons (Fig. 3c) and cell bodies (Fig. S3b) of Cyfip1+/- DIV 3 cortical neurons compared to WT.”

In Cyfip1+/- neurons compared to WT, binding of mCacna1c mRNA to both HuD and HuR proteins is significantly reduced.

“The results revealed a significant reduction in the binding of mCacna1c mRNA to both HuD and HuR proteins in Cyfip1+/- neurons compared to WT.”

Ionomycin did not affect mitochondrial membrane potential in WT neurons.

“Similarly, Ionomycin did not affect mitochondrial membrane potential (measured by TMRE intensity) in WT”

mRNA levels of mCacna1e are significantly reduced in Cyfip1+/- compared to WT.

“we found that the mRNA levels of two of the CYFIP1 targets, mCacna1e and mCacna1i, are significantly reduced in Cyfip1+/- compared to WT (Fig. 4b).”

mRNA levels of mCacna1i are significantly reduced in Cyfip1+/- compared to WT.

“we found that the mRNA levels of two of the CYFIP1 targets, mCacna1e and mCacna1i, are significantly reduced in Cyfip1+/- compared to WT (Fig. 4b).”

The prediction indicates that HuD and HuR have a high probability of binding to mCacna1c, mCacna1e and mCacna1i mRNAs, especially in their 3' UTR regions.

“The prediction indicates that HuD and HuR have a high probability of binding to mCacna1c, mCacna1e and mCacna1i mRNAs, especially in their 3’ UTR regions (Fig. 5b).”

Protein levels of CaV2.3 and CaV3.3 are strikingly reduced in the axonal segment of Cyfip1+/- neurons compared to WT.

“the protein levels of CaV2.3 and CaV3.3 are strikingly reduced in the axonal segment of Cyfip1+/- neurons compared to WT (Fig. 4e, f)”

Ionomycin increased mitochondrial membrane potential in Cyfip1+/- axons to a level comparable to WT.

“but was able to increase it in Cyfip1+/- axons to a level comparable to the WT”

The reduction in CaV1.2, CaV2.3 and CaV3.3 protein levels is normalized at later developmental stages.

“However, this reduction is normalized at later developmental stages (Fig. S4a).”

In vivo, axonal mitochondrial membrane potential in the corpus callosum of P5-6 mice is reduced in Cyfip1+/- brain slices compared to WT.

“To investigate the in vivo relevance of these findings, we measured axonal mitochondrial membrane potential in the corpus callosum of P5–6 mice and observed a reduction in Cyfip1+/- brain slices compared to WT (Fig. 3d).”

Non-target mCacng2 and mCacnb3 mRNAs show no difference in stability between the two genotypes.

“The non-target mCacng2 and mCacnb3 mRNAs showed no difference in stability between the two genotypes (Fig. S4g).”

Protein levels of CaV3.3 (CACNA1I) are significantly reduced in Cyfip1+/- DIV3 neurons compared to WT.

“We found that the protein levels of the three calcium channel targets, CaV1.2 (CACNA1C), CaV2.3 (CACNA1E) and CaV3.3 (CACNA1I), are significantly reduced in Cyfip1+/- DIV 3 neurons compared to WT (Fig. 4c).”

Ionomycin treatment did not affect mitochondrial motility in WT neurons.

“while Ionomycin treatment did not affect mitochondrial motility in WT”

CYFIP1 haploinsufficiency does not affect HuD/Elavl4 and HuR/Elavl1 protein levels.

“However, CYFIP1 haploinsufficiency did not affect HuD/Elavl4 and HuR/Elavl1 protein levels (Fig. S4e).”

CaVγ2 (CACNG2/Stargazin) and CaVβ3 (CACNB3) have comparable mRNA and protein levels between WT and Cyfip1+/- neurons at all developmental stages.

“Conversely, the voltage-gated channel subunits gamma 2 (CaVγ2/CACNG2/Stargazin) and beta-3 (CaVβ3/CACNB3) had comparable mRNA and protein levels between WT and Cyfip1+/- neurons at all developmental stages (Fig. 4b, c, Fig.S4a).”

Bay-K-8644 and Nefiracetam fully rescue the delayed axonal growth in Cyfip1+/- neurons.

“Additionally, Bay-K-8644 and Nefiracetam, two agonists of L-type calcium channels, fully rescue the delayed axonal growth in Cyfip1+/- neurons”

The major axis of mitochondria is elongated in Cyfip1+/- axons.

“The analysis revealed a significantly increased mitochondrial area and elongation of the major axis of mitochondria in Cyfip1+/- axons.”

No difference in ATP levels is found at later stages (P15 and P30) between WT and Cyfip1+/-.

“while no difference was found at later stages (P15 and P30, Fig. S3i, j).”

Cyfip1+/- cortical neurons exhibit reduced ATP compared to WT only at early developmental stages (DIV3).

“Finally, we further investigated mitochondrial function by measuring ATP levels and found that Cyfip1+/- cortical neurons exhibit reduced ATP compared to WT only at early developmental stages (DIV 3) (Fig. S3e, f, g).”

mCacna1i mRNA binding shows no statistically significant difference between Cyfip1+/- and WT neurons.

“In contrast, mCacna1i mRNA showed no statistically significant difference”

mCacna1e mRNA association to HuR shows a trend in Cyfip1+/- neurons compared to WT.

“and a trend in the association to HuR.”

Binding sites identified in human are conserved in mice.

“alignments of the human and mouse sequences (5’UTR-coding-3’UTR) using BLAST (NCBI) show that the binding sites identified in human are conserved in mice”

Protein levels of CaV1.2 (CACNA1C) are significantly reduced in Cyfip1+/- DIV3 neurons compared to WT.

“We found that the protein levels of the three calcium channel targets, CaV1.2 (CACNA1C), CaV2.3 (CACNA1E) and CaV3.3 (CACNA1I), are significantly reduced in Cyfip1+/- DIV 3 neurons compared to WT (Fig. 4c).”

Protein levels of CaV2.3 (CACNA1E) are significantly reduced in Cyfip1+/- DIV3 neurons compared to WT.

“We found that the protein levels of the three calcium channel targets, CaV1.2 (CACNA1C), CaV2.3 (CACNA1E) and CaV3.3 (CACNA1I), are significantly reduced in Cyfip1+/- DIV 3 neurons compared to WT (Fig. 4c).”

mRNA decay of mCacna1c, mCacna1e and mCacna1i is enhanced in Cyfip1+/- neurons after 4 h of Actinomycin D treatment.

“Such a treatment revealed that the mRNA decay of the three calcium channel targets, mCacna1c, mCacna1e and mCacna1i, is enhanced in Cyfip1+/- neurons after 4 h (Fig. 5e).”

Ionomycin reduced the excess mitochondrial motility in Cyfip1+/- axons to a level comparable to WT.

“it was able to reduce the excess motility in Cyfip1+/- axons to a level comparable to the WT”

Ionomycin significantly increased axonal growth in both WT and Cyfip1+/- neurons.

“While Ionomycin significantly increased axonal growth in both WT and Cyfip1+/- neurons (Fig. 6a)”

CYFIP1 binds to HuD/Elavl4 and HuR/Elavl1 proteins in DIV 3 WT cortical neurons, forming a protein complex.

“We performed a CYFIP1 immunoprecipitation on protein extracts from DIV 3 WT cortical neurons and confirmed the binding of CYFIP1 to HuD/Elavl4 and HuR/Elavl1 proteins (Fig. S4d), demonstrating the formation of this protein complex.”

ATP levels in the cortex of P5 mice are reduced in Cyfip1+/- compared with WT.

“In addition, we observed that the ATP levels in the cortex of P5 mice are reduced in Cyfip1+/- compared with WT (Fig. S3h)”

Mitochondrial area is significantly increased in Cyfip1+/- axons.

“The analysis revealed a significantly increased mitochondrial area and elongation of the major axis of mitochondria in Cyfip1+/- axons.”

These mRNAs contain several RBP binding sites, especially on the 3' UTR.

“and these mRNAs contain several RBP binding sites, especially on the 3’ UTR, which suggest that nELAVL proteins could regulate their stability, localization, or translation (Fig. 5a and Fig. S4b).”

Treatment with both Bay-K-8644 and Nefiracetam effectively rescues the delayed axonal growth phenotype in Cyfip1+/- neurons.

“Our results demonstrate that treatment with both agonists effectively rescues the delayed axonal growth phenotype (Fig. 6d)”

mCacna1e mRNA binding to HuD is significantly reduced in Cyfip1+/- neurons compared to WT.

“mCacna1e mRNA exhibited a significant reduction in its binding to HuD”

After Ionomycin treatment, axonal growth rate became comparable in both genotypes.

“the growth rate became comparable in both genotypes”

Arborization is slowed down in Cyfip1+/- mice.

“indicating that arborization is also slowed down”

The increased mitochondrial density observed in the axon may be due to a transport defect.

“suggesting that the increased mitochondrial density observed in the axon may be due to a transport defect”

The in vitro reduced axonal growth recapitulates the in vivo observation.

“This result recapitulated our in vivo observation and strengthened the hypothesis that CYFIP1 may regulate axonal growth in a cell autonomous manner.”

CYFIP1 dysfunction may underlie the connectivity defects observed in adult Cyfip1+/- mice and reported in individuals with ASD and SCZ.

“Together, our findings reveal the crucial role of CYFIP1 in cortical axonal development and suggest that its dysfunction may underlie the connectivity defects observed in vivo in the adult Cyfip1+/- mice and reported in individuals with ASD and SCZ.”

CYFIP1 is crucial for timely axonal development in the neocortex.

“demonstrating that CYFIP1 is crucial for timely axonal development in the neocortex”

CYFIP1 ensures proper callosal development by regulating mRNA metabolism.

“These findings highlight that, by regulating mRNA metabolism, CYFIP1 ensures proper callosal development, offering insights into brain connectivity disruptions underlaying neurodevelopmental disorders.”

Cyfip1 deficiency leads to a delay in axonal growth.

“indicating that Cyfip1 deficiency leads to a delay in axonal growth”

The axonal growth defect in Cyfip1+/- mice may be cell autonomous.

“suggesting that the observed axonal growth defect may be cell autonomous”

CYFIP1 has a crucial function within a specific developmental period which could contribute to the delayed axonal growth phenotype.

“emphasizing its crucial function within a specific developmental period which could contribute to the delay axonal growth phenotype previously observed in those cells.”

This regulation of mitochondrial function by CYFIP1 could critically impact axonal development in Cyfip1+/- cortical neurons.

“which could critically impact axonal development in Cyfip1+/- cortical neurons.”

The rescue by Bay-K-8644 and Nefiracetam demonstrates the role of calcium channels in the observed phenotype.

“further demonstrating the role of these calcium channels in the observed phenotype.”

Calcium channels play a direct role in the axonal growth phenotypes observed in Cyfip1+/- neurons.

“validating the direct role of calcium channels in the axonal growth phenotypes observed in Cyfip1+/- neurons.”

CYFIP1 plays a crucial role in cortical axonal development.

“Here we found a crucial role for the disease-associated protein CYFIP1 in cortical axonal development.”

During cortical axonal development, CYFIP1 regulates axonal protein levels of alpha-1 subunits of CaV channels by controlling their mRNA stability through binding with Hu proteins.

“Altogether, our results demonstrate that, during cortical axonal development, CYFIP1 regulates the axonal protein levels of alpha-1 subunits of CaV channels by controlling their mRNA stability through its binding with Hu proteins.”

Increasing intracellular [Ca2+] successfully restored axonal growth in Cyfip1+/- neurons.

“demonstrating that increasing intracellular [Ca2+] successfully restored axonal growth (Fig. 6a).”

CYFIP1 regulates the membrane expression of voltage-gated calcium channels by controlling the stability of their mRNAs.

“At the molecular level, we demonstrated that CYFIP1 regulates the membrane expression of voltage-gated calcium channels by controlling the stability of their mRNAs.”

mRNAs encoding alpha-1 subunits of CaV channels are regulated at the level of stability, specifically during axonal development, by the ribonucleocomplex constituted by CYFIP1 and Hu proteins.

“Here, using CYFIP1 heterozygosity as a model, we demonstrate that mRNAs encoding for the alpha-1 subunits of CaV channels are regulated at the level of stability, specifically while the axon is developing, by the ribonucleocomplex constituted by CYFIP1 and the Hu proteins (Fig. 5, Fig. 6 and Fig.S4).”

CYFIP1 regulates mitochondrial function through the regulation of intracellular Ca2+ availability.

“Overall, our results suggest that CYFIP1 regulates mitochondrial function through the regulation of intracellular Ca2+ availability”

Bay-K-8644 specifically activates L-type calcium channels.

“Bay-K-8644 specifically activates L-type calcium channels”

• cites [73] Archana, G. M., Arunkumar, R. C. & Omkumar, R. V. Assays for L-type voltage gated calcium channels. Anal. Biochem. 656, 114827 (2022). sourceNot checked — no full text of the source

Mitochondria appear larger and more elongated in Cyfip1+/- axons.

“These results show that mitochondria appear larger and more elongated in Cyfip1⁺/⁻ axons”

CYFIP1 plays a crucial role in neurodevelopmental disorders, especially those marked by disturbed brain connectivity and wiring.

“Our results further support the crucial role of CYFIP1 in neurodevelopmental disorders, especially those marked by disturbed brain connectivity and wiring”

CYFIP1 regulates the mRNA and protein levels of alpha-1 subunits of CaV channels in developing cortical neurons and axons.

“Together, these results demonstrate that CYFIP1 regulates the mRNA and protein levels of alpha-1 subunits of CaV channels in developing cortical neurons and axons”

• AssumptionRests on an assumption: CYFIP1 has no putative RNA binding domains.

CYFIP1's regulatory influence on intracellular Ca2+ levels may underlie the aberrant modulation of mitochondrial function and the observed disruptions in axonal development in Cyfip1+/- cortical neurons.

“Our findings substantiate the hypothesis that, at this very early developmental stage, the regulatory influence of CYFIP1 on intracellular Ca2+ levels may underlie the aberrant modulation of mitochondrial function and the observed disruptions in axonal development found in Cyfip1+/- cortical neurons.”

Upregulation of intracellular calcium was sufficient to rescue the delayed axonal growth and mitochondrial dysfunction observed in Cyfip1+/- neurons.

“Notably, upregulation of intracellular calcium was sufficient to rescue the delayed axonal growth and mitochondrial dysfunction observed in Cyfip1+/- neurons.”

HuD and HuR potentially interact with Cacna1c, Cacna1e, and Cacna1i mRNAs in both species.

“further supporting the potential interaction between HuD and HuR with Cacna1c, Cacna1e, and Cacna1i mRNAs in both species.”

Ionomycin completely rescued the mitochondrial motility phenotype in Cyfip1+/- axons.

“therefore completely rescuing the phenotype (Fig. 6b).”

Appropriate calcium levels play a crucial role in early axonal development.

“suggesting that appropriate calcium levels play a crucial role in early axonal development.”

Increasing intracellular [Ca2+] restores the mitochondrial and axonal phenotypes observed in Cyfip1+/- neurons.

“Altogether, these results demonstrate that increasing intracellular [Ca2+] restores the mitochondrial and axonal phenotypes observed in Cyfip1+/- neurons”

Ionomycin completely rescued the mitochondrial membrane potential phenotype in Cyfip1+/- axons.

“leading, also in this case, to a complete rescue of the phenotype (Fig. 6c).”