title: Actin-independent behavior and membrane deformation exhibited by the four-transmembrane protein M6a.
abstract: M6a is a four-transmembrane protein that is abundantly expressed in the nervous system. Previous studies have shown that over-expression of this protein induces various cellular protrusions, such as neurites, filopodia, and dendritic spines. In this detailed characterization of M6a-induced structures, we found their varied and peculiar characteristics. Notably, the M6a-induced protrusions were mostly devoid of actin filaments or microtubules and exhibited free random vibrating motion. Moreover, when an antibody bound to M6a, the membrane-wrapped protrusions were suddenly disrupted, leading to perturbation of the surrounding membrane dynamics involving phosphoinositide signaling. During single-molecule analysis, M6a exhibited cytoskeleton-independent movement and became selectively entrapped along the cell perimeter in an actin-independent manner. These observations highlight the unusual characteristics of M6a, which may have a significant yet unappreciated role in biological systems.
authors.affiliation: Division of Brain Function, National Institute of Genetics, Graduate University for Advanced Studies (Sokendai), Mishima, Shizuoka, Japan.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Sato
authors.forename: Naoki
authors.initials: N
authors.lastname: Watanabe
authors.forename: Nanae
authors.initials: N
authors.lastname: Fukushima
authors.forename: Sakura
authors.initials: S
authors.lastname: Mita
authors.forename: Tatsumi
authors.initials: T
authors.lastname: Hirata
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D006224:Cricetinae; D018076:DNA, Complementary / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology; D008562:Membrane Glycoproteins / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry*; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods; D015233:Models, Statistical; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D009474:Neurons / Q000378:metabolism; D010716:Phosphatidylinositols / Q000737:chemistry; D013997:Time Factors; D014162:Transfection
chemical_list: D000199:Actins; D018076:DNA, Complementary; C083480:Gpm6a protein, mouse; D008562:Membrane Glycoproteins; D008563:Membrane Lipids; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010716:Phosphatidylinositols; D049452:Green Fluorescent Proteins