Syndecan-2 induces filopodia by active cdc42Hs.
The syndecans, a family of transmembrane heparan sulfate proteoglycans, are ubiquitous molecules whose intracellular function is still unknown. To examine the function of syndecan-2, one of the most abundant heparan sulfate proteoglycan in fibroblasts, we performed transfection studies in COS-1 and Swiss 3T3 cells. Endogenous syndecan-2 colocalized with F-actin in cortical structures. Overexpression of full-length syndecan-2 induced the formation of long filopodia-like structures. These changes correlated with a rearrangement of the actin cytoskeleton, which strongly colocalized with syndecan-2. Overexpression of syndecan-2 lacking the extracellular domain increased the number of microspikes on the cell surface but failed to induce filopodia. Addition of heparin blocked the effect of full-length syndecan-2, suggesting that heparan sulfate chains in the extracellular domain are necessary to induce filopodia. Coexpression of cdc42Hs negative-dominant N17 blocked syndecan-2-induced filopodia and cdc42Hs positive-dominant V12 had a synergic effect. This indicates that active cdc42Hs is necessary for syndecan-2 induction of filopodia. These results provide a link between syndecan-2, actin cytoskeleton, and cdc42Hs.
Granés
F
F
Department of Cell Biology, University of Barcelona, Diagonal 645, Barcelona, 08028, Spain.
García
R
R
Casaroli-Marano
R P
RP
Castel
S
S
Rocamora
N
N
Reina
M
M
Ureña
J M
JM
Vilaró
S
S
D016475:3T3 Cells; D000199:Actins / Q000302:isolation & purification; D000818:Animals; D019556:COS Cells; D002451:Cell Compartmentation; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000648:ultrastructure*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D010446:Peptide Fragments / Q000096:biosynthesis / Q000235:genetics; D011509:Proteoglycans / Q000096:biosynthesis* / Q000235:genetics; D011554:Pseudopodia / Q000648:ultrastructure*; D011994:Recombinant Proteins / Q000096:biosynthesis; D015398:Signal Transduction; D053669:Syndecan-2; D020764:cdc42 GTP-Binding Protein
D000199:Actins; D018797:Cell Cycle Proteins; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D011509:Proteoglycans; D011994:Recombinant Proteins; C508246:Sdc2 protein, mouse; D053669:Syndecan-2; D006493:Heparin; D019204:GTP-Binding Proteins; D020764:cdc42 GTP-Binding Protein