Cdc42-independent activation and translocation of the cytostatic p21-activated protein kinase gamma-PAK by sphingosine.
Autophosphorylation of p21-activated protein kinase gamma-PAK is stimulated at 10 microM sphingosine in vitro and is maximal at 100 microM. Sites autophosphorylated on gamma-PAK in response to sphingosine are identical to those obtained with Cdc42(GTP). Autophosphorylation is paralleled by stimulation of gamma-PAK activity as measured with peptide and protein substrates. In 3T3-L1 cells, sphingosine stimulates the autophosphorylation and activity of gamma-PAK associated with the membrane-containing particulate fraction by 2.8-fold, but does not stimulate the activity of the soluble enzyme. Thus, gamma-PAK is activatable via a Cdc42-independent mechanism, suggesting sphingosine has a role in gamma-PAK activation under conditions of cell stress.
Roig
J
J
Department of Biochemistry, University of California, Riverside, CA 92521, USA. roig@molbio.mgh.harvard.edu
Tuazon
P T
PT
Traugh
J A
JA
D016475:3T3 Cells; D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D004789:Enzyme Activation; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013110:Sphingosine / Q000378:metabolism* / Q000494:pharmacology; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*; D054462:p21-Activated Kinases
D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C515909:Pak2 protein, mouse; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D020764:cdc42 GTP-Binding Protein; D013110:Sphingosine