Palladin interacts with SH3 domains of SPIN90 and Src and is required for Src-induced cytoskeletal remodeling.
Palladin and SPIN90 are widely expressed proteins, which participate in modulation of actin cytoskeleton by binding to a variety of scaffold and signaling molecules. Cytoskeletal reorganization can be induced by activation of signaling pathways, including the PDGF receptor and Src tyrosine kinase pathways. In this study we have analyzed the interplay between palladin, SPIN90 and Src and characterized the role of palladin and SPIN90 in PDGF and Src-induced cytoskeletal remodeling. We show that the SH3 domains of SPIN90 and Src directly bind palladin's poly-proline sequence and the interaction controls intracellular targeting of SPIN90. In PDGF-treated cells, palladin and SPIN90 co-localize in actin-rich membrane ruffles and lamellipodia. The effect of PDGF on the cytoskeleton is at least partly mediated by the Src kinase since PP2, a selective Src kinase family inhibitor, blocked PDGF-induced changes. Furthermore, expression of active Src kinase resulted in coordinated translocation of both palladin and SPIN90 to membrane protrusions. Knock-down of endogenous SPIN90 did not inhibit Src-induced cytoskeletal rearrangement, whereas knock-down of palladin resulted in cytoskeletal disorganization and inhibition of remodeling. Further studies showed that palladin is tyrosine phosphorylated in cells expressing active Src indicating bidirectional interplay between palladin and Src. These results may have implications in understanding the invasive and metastatic phenotype of neoplastic cells induced by Src.
Rönty
Mikko
M
Department of Pathology, Neuroscience Program, Biomedicum Helsinki, University of Helsinki and Helsinki University Hospital, Helsinki, Finland. mikko.ronty@helsinki.fi
Taivainen
Anu
A
Heiska
Leena
L
Otey
Carol
C
Ehler
Elisabeth
E
Song
Woo Keun
WK
Carpen
Olli
O
D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003598:Cytoskeletal Proteins / Q000172:deficiency / Q000378:metabolism*; D003599:Cytoskeleton / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D009124:Muscle Proteins / Q000737:chemistry* / Q000378:metabolism*; D010750:Phosphoproteins / Q000172:deficiency / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D022502:Stress Fibers / Q000187:drug effects; D013347:Subcellular Fractions / Q000187:drug effects; D014162:Transfection; D018909:src Homology Domains; D019061:src-Family Kinases / Q000737:chemistry* / Q000378:metabolism*
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; D009124:Muscle Proteins; C486062:NCKIPSD protein, human; C412722:PALLD protein, human; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D019000:Phosphotyrosine; D019061:src-Family Kinases