Endocytic protein intersectin-l regulates actin assembly via Cdc42 and N-WASP.
Intersectin-s is a modular scaffolding protein regulating the formation of clathrin-coated vesicles. In addition to the Eps15 homology (EH) and Src homology 3 (SH3) domains of intersectin-s, the neuronal variant (intersectin-l) also has Dbl homology (DH), pleckstrin homology (PH) and C2 domains. We now show that intersectin-l functions through its DH domain as a guanine nucleotide exchange factor (GEF) for Cdc42. In cultured cells, expression of DH-domain-containing constructs cause actin rearrangements specific for Cdc42 activation. Moreover, in vivo studies reveal that stimulation of Cdc42 by intersectin-l accelerates actin assembly via N-WASP and the Arp2/3 complex. N-WASP binds directly to intersectin-l and upregulates its GEF activity, thereby generating GTP-bound Cdc42, a critical activator of N-WASP. These studies reveal a role for intersectin-l in a novel mechanism of N-WASP activation and in regulation of the actin cytoskeleton.
Hussain
N K
NK
Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, H3A 2B4, Canada.
Jenna
S
S
Glogauer
M
M
Quinn
C C
CC
Wasiak
S
S
Guipponi
M
M
Antonarakis
S E
SE
Kay
B K
BK
Stossel
T P
TP
Lamarche-Vane
N
N
McPherson
P S
PS
D000199:Actins / Q000378:metabolism*; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D018613:Microscopy, Confocal; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism; D010590:Phalloidine / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*
D000199:Actins; D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; C495771:WASL protein, human; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; C115919:intersectin 1; D010590:Phalloidine; D020764:cdc42 GTP-Binding Protein