Interaction of microtubule-associated protein 2 with actin filaments
Abstract
The interaction of unphosphorylated and phosphorylated microtubule-associated protein 2 (MAP-2) with actin filaments was examined by electron microscopic, electrophoretic, and dark-field light microscopic techniques. Unphosphorylated MAP-2 was observed to cross-link and bundle individual actin filaments. Chymotryptic fragments of MAP-2 protein were produced which bound to, but could not cross-link, actin polymer; these fragments encompassed the tubulin binding domain of MAP-2. The phosphorylation of intact MAP-2, by means of endogenous protein kinases, inhibited the ability of this molecule to cross-link and bundle actin filaments. Phosphorylation did not, however, inhibit the binding of MAP-2 to F-actin. The chymotryptic fragments of phosphorylated MAP-2 that retained their ability to bind to actin and promote microtubule assembly also encompassed the tubulin binding domain of this molecule. An analysis of MAP-2 fragments by nonequilibrium pH gradient electrophoresis indicated that most of the polypeptide backbone is relatively acidic with the exception of the tubulin binding domain. This region was determined to be the most basic (positively charged) region of the MAP-2 molecule. Biochemical and morphological evidence is presented to demonstrate that both unphosphorylated MAP-2 and phosphorylated MAP-2 have the capacity to use actin, in addition to microtubules, as a separate anchoring substrate. The presence of tubulin, however, strongly inhibits the interaction of MAP-2 w…
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MAPs bundle actin filaments and cross-link the cellular cytoskeleton formed by microtubules and actin filaments.
“In addition, MAPs bundle actin filaments and cross-link the cellular cytoskeleton formed by microtubules and actin filaments (Fig. 1a)3–10.”
From Multivalent cross-linking of actin filaments and microtubules through the microtubule-associated protein Tau (2017) · cites this paper as [5]
Binding of Tau and MAP2 to filamentous actin results in actin cross-linking and filament bundling.
“Binding of Tau and MAP2 to filamentous actin results in actin cross-linking and filament bundling5, 6, 14, 22, 40–43.”
From Multivalent cross-linking of actin filaments and microtubules through the microtubule-associated protein Tau (2017) · cites this paper as [5]
Binding to F-actin can be retained while cross-linking activity is disrupted.
“At the same time, binding to F-actin can be retained, but the cross-linking activity disrupted.”
From Multivalent cross-linking of actin filaments and microtubules through the microtubule-associated protein Tau (2017) · cites this paper as [5]
A C-terminal fragment and a peptide corresponding to the second microtubule-binding repeat bind actin but are incapable of mediating actin cross-linking.
“For example, a C-terminal fragment and a peptide corresponding to the second microtubule-binding repeat bind actin, but are incapable of mediating actin cross-linking5, 17.”
From Multivalent cross-linking of actin filaments and microtubules through the microtubule-associated protein Tau (2017) · cites this paper as [5]
Phosphorylation at the KXGS motifs decreases the affinity of Tau for both microtubules and F-actin.
“While our as well as previous biophysical studies demonstrated that phosphorylation at the KXGS motifs decreases the affinity of Tau for both microtubules and F-actin, cellular studies showed that phosphorylation of the KXGS motifs cause MAP2 and Tau to localize to the actin cytoskeleton9.”
From Multivalent cross-linking of actin filaments and microtubules through the microtubule-associated protein Tau (2017) · cites this paper as [5]
Phosphorylation by endogenous protein kinases inhibits the ability of Tau and MAP2 to cross-link and bundle actin filaments.
“In addition, phosphorylation by endogenous protein kinases inhibits the ability of Tau and MAP2 to cross-link and bundle actin filaments5, 6.”
From Multivalent cross-linking of actin filaments and microtubules through the microtubule-associated protein Tau (2017) · cites this paper as [5]
Cites
De Camilli, P., Miller, P. E., Navone, F., Theurkauf, W. E., & Vallee, R. B. (1984) · Neuroscience · doi:10.1016/0306-4522(84)90194-5 · Cited by 381 · see citing works
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Cabrales Fontela, Y., Kadavath, H., Biernat, J., Riedel, D., Mandelkow, E., & Zweckstetter, M. (2017) · Nature Communications · doi:10.1038/s41467-017-02230-8 · Cited by 148 · see citing works
- Authors
- Sattilaro, R. F.
- Corresponding author
- Sattilaro, Richard F.
- Venue
- Biochemistry
- Publisher
- American Chemical Society (ACS)
- Published
- 1986-04-01
- Volume
- 25
- Issue
- 8
- Pages
- 2003-2009
- ISSN
- 0006-2960 (ISSN-L)
- 1520-4995
- OpenAlex
- W2093209350
- Cited by
- 122
- References
- 1
- Citations by year
- 2024: 1 · 2021: 4 · 2020: 1 · 2019: 6 · 2018: 1 · 2017: 2 · 2016: 2 · 2015: 2 · 2013: 1 · 2012: 3
- FWCI
- 3.88
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Biochemistry (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Institutes of Health (AM21672)
- National Institute of General Medical Sciences (GM-32556)
- National Institute of Neurological Disorders and Stroke (NS 20560)
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Microtubule and mitosis dynamics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Cellular Mechanics and Interactions
- Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
- Keywords
- MAP2, actin filament cross-linking, actin bundling, chymotryptic fragments, protein kinases, microtubule assembly, protein charge distribution
- MeSH terms
- Actins, Animals, Brain, Cattle, Electrophoresis, Polyacrylamide Gel, Microscopy, Electron, Microtubule-Associated Proteins, Muscles, Phosphorylation, Rabbits
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