Interaction of SPIN90 with the Arp2/3 complex mediates lamellipodia and actin comet tail formation.
The appropriate regulation of the actin cytoskeleton is essential for cell movement, changes in cell shape, and formation of membrane protrusions like lamellipodia and filopodia. Moreover, several regulatory proteins affecting actin dynamics have been identified in the motile regions of cells. Here, we provide evidence for the involvement of SPIN90 in the regulation of actin cytoskeleton and actin comet tail formation. SPIN90 was distributed throughout the cytoplasm in COS-7 cells, but exposing the cells to platelet-derived growth factor (PDGF) caused a redistribution of SPIN90 to the cell cortex and the formation of lamellipodia (or membrane ruffles), both of which were dramatically inhibited in SPIN90-knockdown cells. In addition, the binding of the C terminus of SPIN90 with both the Arp2/3 complex (actin-related proteins Arp 2 and Arp 3) and G-actin activates the former, leading to actin polymerization in vitro. And when coexpressed with phosphatidylinositol 4-phosphate 5 kinase, SPIN90 was observed within actin comet tails. Taken these findings suggest that SPIN90 participates in reorganization of the actin cytoskeleton and in actin-based cell motility.
Kim
Dae Joong
DJ
Department of Life Science and Molecular Disease Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.
Kim
Sung Hyun
SH
Lim
Chol Seung
CS
Choi
Kyu Yeong
KY
Park
Chun Shik
CS
Sung
Bong Hwan
BH
Yeo
Myeong Gu
MG
Chang
Sunghoe
S
Kim
Jin-Kyu
JK
Song
Woo Keun
WK
D008841:Actin Cytoskeleton / Q000378:metabolism*; D051377:Actin-Related Protein 2 / Q000378:metabolism*; D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism; D051378:Actin-Related Protein 3 / Q000378:metabolism*; D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002465:Cell Movement / Q000502:physiology; D002522:Chlorocebus aethiops; D006224:Cricetinae; D006801:Humans; D007668:Kidney / Q000166:cytology; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D011554:Pseudopodia / Q000378:metabolism*; D034741:RNA, Small Interfering; D014162:Transfection
D051377:Actin-Related Protein 2; D051376:Actin-Related Protein 2-3 Complex; D051378:Actin-Related Protein 3; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D009124:Muscle Proteins; C486062:NCKIPSD protein, human; D034741:RNA, Small Interfering; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase