Microtubule elongation along actin filaments induced by microtubule-associated protein 4 contributes to the formation of cellular protrusions
- 14 April 2020
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Biochemistry
- Vol. 168 (3), 295-303
- https://doi.org/10.1093/jb/mvaa046
Abstract
Actin-microtubule crosstalk is implicated in the formation of cellular protrusions, but the mechanism remains unclear. In this study, we examined the regulation of cell protrusion involving a ubiquitously expressed microtubule-associated protein (MAP) 4, and its superfamily proteins, neuronal MAP2 and tau. Fluorescence microscopy revealed that these MAPs bound to F-actin and microtubules simultaneously, and formed F-actin/microtubule hybrid bundles. The hybrid bundle-forming activity was in the order of MAP2 > MAP4 ≫ tau. Interestingly, the microtubule assembly-promoting activity of MAP4 and MAP2, but not of tau, was upregulated by their interaction with F-actin. When MAP4 was overexpressed in NG108-15 cells, the number of cell processes and maximum process length of each cell increased significantly by 28% and 30%, respectively. Super-resolution microscopy revealed that 95% of microtubules in cell processes colocalized with F-actin, and MAP4 was always found in their vicinity. These results suggest that microtubule elongation along F-actin induced by MAP4 contributes to the formation of cellular protrusions. Since MAP4, MAP2 and tau had different crosstalk activity between F-actin and microtubules, it is likely that the functional differentiation of these MAPs is a driving force for neural evolution, causing significant changes in cell morphology.Keywords
Funding Information
- JSPS KAKENHI (JP16K14704, JP24117008, JP16H03288)
- AMED-CREST (#19gm1210007s0101)
This publication has 53 references indexed in Scilit:
- Microtubule-associated protein 4 binds to actin filaments and modulates their propertiesThe Journal of Biochemistry, 2011
- Distinct neuronal localization of microtubule-associated protein 4 in the mammalian brainNeuroscience Letters, 2010
- The proline-rich domain of tau plays a role in interactions with actinBMC Cell Biology, 2009
- Differences in the regulation of microtubule stability by the pro‐rich region variants of microtubule‐associated protein 4FEBS Letters, 2006
- Identification of the 190kD microtubule-associated protein in cultured fibroblasts and its association with interphase and mitotic microtubules.Cell Structure and Function, 1987
- Immunofluorescence localization of HeLa cell microtubule-associated proteins on microtubules in vitro and in vivo.The Journal of cell biology, 1980
- Neuroblastoma cells recapitulate their detailed neurite morphologies after reversible microtubule disassemblyCell, 1980
- Physical and chemical properties of purified tau factor and the role of tau in microtubule assemblyJournal of Molecular Biology, 1977
- Purification of tau, a microtubule-associated protein that induces assembly of microtubules from purified tubulinJournal of Molecular Biology, 1977
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970