title: Affixin interacts with alpha-actinin and mediates integrin signaling for reorganization of F-actin induced by initial cell-substrate interaction.
abstract: The linking of integrin to cytoskeleton is a critical event for an effective cell migration. Previously, we have reported that a novel integrin-linked kinase (ILK)-binding protein, affixin, is closely involved in the linkage between integrin and cytoskeleton in combination with ILK. In the present work, we demonstrated that the second calponin homology domain of affixin directly interacts with alpha-actinin in an ILK kinase activity-dependent manner, suggesting that integrin-ILK signaling evoked by substrate adhesion induces affixin-alpha-actinin interaction. The overexpression of a peptide corresponding to the alpha-actinin-binding site of affixin as well as the knockdown of endogenous affixin by small interference RNA resulted in the blockade of cell spreading. Time-lapse observation revealed that in both experiments cells were round with small peripheral blebs and failed to develop lamellipodia, suggesting that the ILK-affixin complex serves as an integrin-anchoring site for alpha-actinin and thereby mediates integrin signaling to alpha-actinin, which has been shown to play a critical role in actin polymerization at focal adhesions.
authors.affiliation: The First Dept. of Internal Medicine, Yokohama City University School of Medicine, 3-9 Fuku-ura, Kanazawa-ku, Yokohama 236-0004, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamaji
authors.forename: Atsushi
authors.initials: A
authors.lastname: Suzuki
authors.forename: Heiwa
authors.initials: H
authors.lastname: Kanamori
authors.forename: Wataru
authors.initials: W
authors.lastname: Mishima
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Yoshimi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Takasaki
authors.forename: Maki
authors.initials: M
authors.lastname: Takabayashi
authors.forename: Katsumichi
authors.initials: K
authors.lastname: Fujimaki
authors.forename: Shin
authors.initials: S
authors.lastname: Fujisawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Ohno
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ishigatsubo
mesh_terms: D000185:Actinin / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D000199:Actins / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D016466:CHO Cells; D019556:COS Cells; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D022081:Cell Surface Extensions / Q000378:metabolism* / Q000648:ultrastructure; D006224:Cricetinae; D015536:Down-Regulation / Q000235:genetics; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D008840:Microfilament Proteins; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D011554:Pseudopodia / Q000378:metabolism / Q000648:ultrastructure; D034622:RNA Interference; D015398:Signal Transduction / Q000502:physiology; D000099200:Scaffold Protein ILK; D000096985:Calponins
chemical_list: D000185:Actinin; D000199:Actins; D016023:Integrins; D008840:Microfilament Proteins; D010455:Peptides; D017346:Protein Serine-Threonine Kinases; D000099200:Scaffold Protein ILK; C486590:PARVA protein, human; D000096985:Calponins; C486591:PARVB protein, human