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Cited by 10Amyotrophic Lateral Sclerosis ResearchHeat shock proteins researchUbiquitin and proteasome pathways

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ALS mutations disrupt self-association between the ubiquilin STI1 hydrophobic groove and internal placeholder sequences

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Onwunma, Joan, Binsabaan, Saeed, Allen, Shawn P, Thanthirige, Sachini R, Gaur, Deepika, Sankaran, Banumathi, Wohlever, Matthew L·2026·The EMBO Journal
DOI 10.1038/s44318-026-00745-9PMC PMC11257586

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Abstract

Ubiquilins are molecular chaperones that play multifaceted roles in proteostasis, with point mutations in UBQLN2 leading to altered phase-separation properties and amyotrophic lateral sclerosis (ALS). Our mechanistic understanding of this essential process has been hindered by a lack of structural information on the STI1 domain, which is essential for ubiquilin chaperone activity and phase separation. Here, we present the first crystal structure of a ubiquilin-family STI1 domain bound to a transmembrane domain (TMD), and show that ALS mutations disrupt the STI1-TMD interaction. We further demonstrate that ubiquilins contain multiple conserved internal sequences that bind to the STI1 domain, including the PXX-repeat region that is a hotspot for ALS mutations. We propose that these placeholder sequences prevent solvent exposure of the STI1 hydrophobic groove and contribute to the multivalency that drives ubiquilin phase-separation. Together, this work provides a new paradigm for understanding how STI1 domains modulate ubiquilin chaperone activity and phase separation, and offers insights into the molecular basis of ALS pathogenesis.

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Research works printed but not linked: 56

  1. Acharya N, Daniel EA, Dao TP, Niblo JK, Mulvey EO, Sukenik S, Kraut DA, Roelofs J, Castañeda CA (2026) STI1 domain engages transient helices to mediate Dsk2 phase separation and proteasome condensation. EMBO J. https://doi.org/10.1038/s44318-026-00696-1 · DOI
  2. Adams PD, Afonine PV, Bunkóczi G, Chen VB, Davis IW, Echols N, Headd JJ, Hung L-W, Kapral GJ, Grosse-Kunstleve RW et al (2010) PHENIX: a comprehensive Python-based system for macromolecular structure solution. Acta Crystallogr Sect D: Biol Crystallogr 66:213–221 · DOI · Paper page
  3. Agirre J, Atanasova M, Bagdonas H, Ballard CB, Baslé A, Beilsten-Edmands J, Borges RJ, Brown DG, Burgos-Mármol JJ, Berrisford JM et al (2023) The CCP4 suite: integrative software for macromolecular crystallography. Acta Crystallogr Sect D 79:449–461 · DOI
  4. Alexander EJ, Niaki AG, Zhang T, Sarkar J, Liu Y, Nirujogi RS, Pandey A, Myong S, Wang J (2018) Ubiquilin 2 modulates ALS/FTD-linked FUS–RNA complex dynamics and stress granule formation. Proc Natl Acad Sci USA 115(49):E11485–E11494 · DOI
  5. Battye TGG, Kontogiannis L, Johnson O, Powell HR, Leslie AGW (2011) iMOSFLM: a new graphical interface for diffraction-image processing with MOSFLM. Acta Crystallogr Sect D: Biol Crystallogr 67:271–281 · DOI
  6. Bertram L, Hiltunen M, Parkinson M, Ingelsson M, Lange C, Ramasamy K, Mullin K, Menon R, Sampson AJ, Hsiao MY et al (2005) Family-based association between Alzheimer’s disease and variants in UBQLN1. N Engl J Med 352:884–894 · DOI
  7. Black HH, Hanson JL, Roberts JE, Leslie SN, Campodonico W, Ebmeier CC, Holling GA, Tay JW, Matthews AM, Ung E et al (2023) UBQLN2 restrains the domesticated retrotransposon PEG10 to maintain neuronal health in ALS. eLife 12:e79452 · DOI
  8. Conicella AE, Zerze GH, Mittal J, Fawzi NL (2016) ALS mutations disrupt phase separation mediated by α-helical structure in the TDP-43 low-complexity c-terminal domain. Structure 24:1537–1549 · DOI
  9. Dantuma NP, Heinen C, Hoogstraten D (2009) The ubiquitin receptor Rad23: at the crossroads of nucleotide excision repair and proteasomal degradation. DNA Repair 8:449–460 · DOI
  10. Dao TP, Kolaitis R-M, Kim HJ, O’Donovan K, Martyniak B, Colicino E, Hehnly H, Taylor JP, Castañeda CA (2018) Ubiquitin modulates liquid-liquid phase separation of UBQLN2 via disruption of multivalent interactions. Mol Cell 69:965–978.e6 · DOI
  11. Dao TP, Martyniak B, Canning AJ, Lei Y, Colicino EG, Cosgrove MS, Hehnly H, Castañeda CA (2019) ALS-linked mutations affect UBQLN2 oligomerization and phase separation in a position- and amino acid-dependent manner. Structure 27:937–951.e5 · DOI
  12. Dao TP, Rajendran A, Galagedera SKK, Haws W, Castañeda CA (2024) Short disordered termini and proline-rich domain are major regulators of UBQLN1/2/4 phase separation. Biophys J 123:1449–1457 · DOI
  13. Dao TP, Yang Y, Presti MF, Cosgrove MS, Hopkins JB, Ma W, Loh SN, Castañeda CA (2022) Mechanistic insights into enhancement or inhibition of phase separation by different polyubiquitin chains. EMBO Rep 23:e55056 · DOI
  14. Edens BM, Yan J, Miller N, Deng H-X, Siddique T, Ma YC (2017) A novel ALS-associated variant in UBQLN4 regulates motor axon morphogenesis. eLife 6:e25453 · DOI
  15. Emsley P, Lohkamp B, Scott WG, Cowtan K (2010) Features and development of Coot. Acta Crystallogr Sect D, Biol Crystallogr 66:486–501 · DOI · Paper page
  16. Fahed AC, McDonough B, Gouvion CM, Newell KL, Dure LS, Bebin M, Bick AG, Seidman JG, Harter DH, Seidman CE (2014) UBQLN2 mutation causing heterogeneous X-linked dominant neurodegeneration. Ann Neurol 75:793–798 · DOI
  17. Fraser JS, Merlie JP, Echols N, Weisfield SR, Mignot T, Wemmer DE, Zusman DR, Alber T (2007) An atypical receiver domain controls the dynamic polar localization of the Myxococcus xanthus social motility protein FrzS. Mol Microbiol 65:319–332 · DOI
  18. Fry MY, Saladi SM, Clemons WM (2021a) The STI1-domain is a flexible alpha-helical fold with a hydrophobic groove. Protein Sci 30:882–898 · DOI
  19. Fry MY, Saladi SM, Cunha A, Clemons WM (2021b) Sequence-based features that are determinant for tail-anchored membrane protein sorting in eukaryotes. Traffic 22:306–318 · DOI
  20. Gaur D, Wohlever ML (2025) A suite of pre-assembled, pET28b-based Golden Gate vectors for efficient protein engineering and expression. Protein Sci 34:e70106 · DOI
  21. Gerson JE, Linton H, Xing J, Sutter AB, Kakos FS, Ryou J, Liggans N, Sharkey LM, Safren N, Paulson HL et al (2021) Shared and divergent phase separation and aggregation properties of brain-expressed ubiquilins. Sci Rep 11:287 · DOI
  22. Guna A, Hegde RS (2018) Transmembrane domain recognition during membrane protein biogenesis and quality control. Curr Biol 28:R498–R511 · DOI
  23. Guna A, Stevens TA, Inglis AJ, Replogle JM, Esantsi TK, Muthukumar G, Shaffer KCL, Wang ML, Pogson AN, Jones JJ et al (2022) MTCH2 is a mitochondrial outer membrane protein insertase. Science 378:317–322 · DOI
  24. Hegde RS, Keenan RJ (2022) The mechanisms of integral membrane protein biogenesis. Nat Rev Mol Cell Bio 23:107–124 · DOI
  25. Hjerpe R, Bett JS, Keuss MJ, Solovyova A, McWilliams TG, Johnson C, Sahu I, Varghese J, Wood N, Wightman M et al (2016) UBQLN2 mediates autophagy-independent protein aggregate clearance by the proteasome. Cell 166:935–949 · DOI
  26. Itakura E, Zavodszky E, Shao S, Wohlever ML, Keenan RJ, Hegde RS (2016) Ubiquilins chaperone and triage mitochondrial membrane proteins for degradation. Mol Cell 63(1):21–33 · DOI
  27. Kleijnen MF, Shih AH, Zhou P, Kumar S, Soccio RE, Kedersha NL, Gill G, Howley PM (2000) The hPLIC proteins may provide a link between the ubiquitination machinery and the proteasome. Mol Cell 6:409–419 · DOI
  28. Kurlawala Z, Shah PP, Shah C, Beverly LJ (2017) The STI and UBA domains of UBQLN1 are critical determinants of substrate interaction and proteostasis. J Cell Biochem 118(8):2261–2270 · DOI
  29. Kurochkina N, Guha U (2013) SH3 domains: modules of protein–protein interactions. Biophys Rev 5:29–39 · DOI
  30. Kyte J, Doolittle RF (1982) A simple method for displaying the hydropathic character of a protein. J Mol Biol 157:105–132 · DOI
  31. Lau DHW, Hartopp N, Welsh NJ, Mueller S, Glennon EB, Mórotz GM, Annibali A, Gomez-Suaga P, Stoica R, Paillusson S et al (2018) Disruption of ER−mitochondria signalling in fronto-temporal dementia and related amyotrophic lateral sclerosis. Cell Death Dis 9:327 · DOI
  32. Le NTT, Chang L, Kovlyagina I, Georgiou P, Safren N, Braunstein KE, Kvarta MD, Dyke AMV, LeGates TA, Philips T et al (2016) Motor neuron disease, TDP-43 pathology, and memory deficits in mice expressing ALS–FTD-linked UBQLN2 mutations. Proc Natl Acad Sci USA 113:E7580–E7589 · DOI
  33. Lin K-F, Fry MY, Saladi SM, Clemons WM (2021) Molecular basis of tail-anchored integral membrane protein recognition by the cochaperone Sgt2. J Biol Chem 296:100441 · DOI
  34. Ma Q, Xin J, Peng Q, Li N, Sun S, Hou H, Ma G, Wang N, Zhang L, Tam KY et al (2023) UBQLN2 and HSP70 participate in Parkin-mediated mitophagy by facilitating outer mitochondrial membrane rupture. EMBO Rep 24:e55859 · DOI
  35. Manigat FO, Connell LB, Stewart BN, LePabic A-R, Tessier CJG, Emlaw JR, Calvert ND, Rössl A, Shuhendler AJ, daCosta CJB et al (2024) pUdOs: concise plasmids for bacterial and mammalian cells. ACS Synth Biol 13:485–497 · DOI
  36. Mateja A, Paduch M, Chang H-Y, Szydlowska A, Kossiakoff AA, Hegde RS, Keenan RJ (2015) Protein targeting. Structure of the Get3 targeting factor in complex with its membrane protein cargo. Science 347:1152–1155 · DOI
  37. Maurer SK, Mayer MP, Ward SJ, Boudjema S, Halawa M, Zhang J, Caulton SG, Emsley J, Dreveny I (2023) Ubiquitin-specific protease 11 structure in complex with an engineered substrate mimetic reveals a molecular feature for deubiquitination selectivity. J Biol Chem 299:105300 · DOI
  38. McCoy AJ, Grosse-Kunstleve RW, Adams PD, Winn MD, Storoni LC, Read RJ, IUCr (2007) Phaser crystallographic software. J Appl Crystallogr 40:658–674 · DOI · Paper page
  39. Pleiner T, Hazu M, Tomaleri GP, Nguyen VN, Januszyk K, Voorhees RM (2023) A selectivity filter in the ER membrane protein complex limits protein misinsertion at the ER. J Cell Biol 222:e202212007 · DOI
  40. Portz B, Lee BL, Shorter J (2021) FUS and TDP-43 phases in health and disease. Trends Biochem Sci 46:p550–p563 · DOI
  41. Rajendran A, Castañeda CA (2025) Protein quality control machinery: regulators of condensate architecture and functionality. Trends Biochem Sci 50:P106–P120 · DOI
  42. Rao M, Okreglak V, Chio US, Cho H, Walter P, Shan S (2016) Multiple selection filters ensure accurate tail-anchored membrane protein targeting. eLife 5:e21301 · DOI
  43. Renaud L, Picher-Martel V, Codron P, Julien J-P (2019) Key role of UBQLN2 in pathogenesis of amyotrophic lateral sclerosis and frontotemporal dementia. Acta Neuropathol Commun 7:103 · DOI
  44. Richardson JS, Richardson DC (1988) Amino acid preferences for specific locations at the ends of α helices. Science 240:1648–1652 · DOI
  45. Riley JF, Fioramonti PJ, Rusnock AK, Hehnly H, Castañeda CA (2021) ALS-linked mutations impair UBQLN2 stress-induced biomolecular condensate assembly in cells. J Neurochem 159:145–155 · DOI
  46. Safren N, Dao TP, Mohan HM, Huang C, Trotter B, Castañeda CA, Paulson H, Barmada S, Sharkey LM (2024) Pathogenic mutations in UBQLN2 exhibit diverse aggregation propensity and neurotoxicity. Sci Rep 14:6049 · DOI
  47. Shimizu Y, Inoue A, Tomari Y, Suzuki T, Yokogawa T, Nishikawa K, Ueda T (2001) Cell-free translation reconstituted with purified components. Nat Biotechnol 19:751–755 · DOI
  48. Stefer S, Reitz S, Wang F, Wild K, Pang Y-Y, Schwarz D, Bomke J, Hein C, Löhr F, Bernhard F et al (2011) Structural basis for tail-anchored membrane protein biogenesis by the Get3-receptor complex. Science 333:758–762 · DOI
  49. Stieren ES, Ayadi AE, Xiao Y, Siller E, Landsverk ML, Oberhauser AF, Barral JM, Boehning D (2011) Ubiquilin-1 is a molecular chaperone for the amyloid precursor protein. J Biol Chem 286:35689–35698 · DOI
  50. Takei T, Sasazawa Y, Noshiro D, Kitagawa M, Kataura T, Hirawake-Mogi H, Kawauchi E, Nakano Y, Tashiro E, Saitoh T et al (2025) Ubiquilin-2 liquid droplets catalyze α-synuclein fibril formation. EMBO J 44:6527–6555 · DOI
  51. Thumbadoo KM, Dieriks BV, Murray HC, Swanson MEV, Yoo JH, Mehrabi NF, Turner C, Dragunow M, Faull RLM, Curtis MA et al (2024) Hippocampal aggregation signatures of pathogenic UBQLN2 in amyotrophic lateral sclerosis and frontotemporal dementia. Brain 147:3547–3561 · DOI
  52. Voorhees RM, Hegde RS (2016) Structure of the Sec61 channel opened by a signal sequence. Science 351:88–91 · DOI
  53. Walters KJ, Kleijnen MF, Goh AM, Wagner G, Howley PM (2002) Structural studies of the interaction between ubiquitin family proteins and proteasome subunit S5a. Biochemistry 41:1767–1777 · DOI
  54. Whiteley AM, Prado MA, Peng I, Abbas AR, Haley B, Paulo JA, Reichelt M, Katakam A, Sagolla M, Modrusan Z et al (2017) Ubiquilin1 promotes antigen-receptor mediated proliferation by eliminating mislocalized mitochondrial proteins. eLife 6:e26435 · DOI
  55. Williams CJ, Headd JJ, Moriarty NW, Prisant MG, Videau LL, Deis LN, Verma V, Keedy DA, Hintze BJ, Chen VB et al (2018) MolProbity: more and better reference data for improved all-atom structure validation. Protein Sci 27:293–315 · DOI · Paper page
  56. Zheng T, Yang Y, Castañeda CA (2020) Structure, dynamics and functions of UBQLNs: at the crossroads of protein quality control machinery. Biochem J 477:3471–3497 · DOI

Metadata

Authors
Onwunma, J., Binsabaan, S., Allen, S. P., Thanthirige, S. R., Gaur, D., Sankaran, B., & Wohlever, M. L.
Affiliations
  • University of Toledo (US)
  • University of Pittsburgh (US)
  • Lawrence Berkeley National Laboratory (US)
Corresponding author
Wohlever, Matthew L
ORCID
Venue
The EMBO Journal
Publisher
Springer Science and Business Media LLC
Published
2026-03-20
Volume
45
Issue
8
Pages
2694-2711
ISSN
  • 0261-4189 (ISSN-L)
  • 1460-2075
DOI
10.1038/s44318-026-00745-9
PMC
PMC11257586
OpenAlex
W7138894650
Cited by
10
References
4
Citations by year
2026: 5
FWCI
20.85
Type
journal article
Language
en
Open access
Licence
Locations
  • The EMBO Journal (publishedVersion, cc-by)
  • bioRxiv (Cold Spring Harbor Laboratory) (acceptedVersion, cc-by-nc-nd)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by-nc-nd)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • HHS | National Institutes of Health (R35 GM137904-01S2, P30 GM124169-01)
  • National Science Foundation (CAREER Award 2343131)
Topics
  • Health Sciences › Medicine › Clinical Neurology › Amyotrophic Lateral Sclerosis Research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Heat shock proteins research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Ubiquitin and proteasome pathways
Keywords
amyotrophic lateral sclerosis, ubiquilin, UBQLN2, molecular chaperones, phase separation, hydrophobic groove, transmembrane domain, crystal structure, ALS mutations, proteostasis

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