Basic fibroblast growth factor-induced translocation of p21-activated kinase to the membrane is independent of phospholipase C-gamma1 in the differentiation of PC12 cells.
p21-activated kinase (PAK) targeting to the plasma membrane is essential for PC12 cell neurite outgrowth. Phospholipase C-gamma1 (PLC-gamma1) can mediate the PAK translocation in response to growth factors, since PLC-gamma1 binds to both tyrosine-phosphorylated receptor tyrosine kinases and PAK through its SH2 and SH3 domain, respectively. In the present study, we examined a potential role for PLC-gamma1 in the basic fibroblast growth factor (bFGF)-induced PAK translocation using stable PC12 cell lines that overexpress in a tetracycline-inducible manner either the wild-type FGFR-1 or the Y766F FGFR-1 mutant. Phosphatidylinositol hydrolysis was increased 6.5-fold in response to bFGF in the wild type cells but negligible in the mutant cells. The recombinant GST-PLC-gamma1 SH3 was able to bind to PAK1 but not GST alone. However, examination of PLC-gamma1 as an adaptor for translocation of PAK1 in cells showed that both cells transfected with pEGFP-PAK1 was able to differentiate for 24 h, as visualized by laser confocal microscopy. Translocation of PAK1 to growth cones occurs at similar levels in both wild and mutant cells. These results suggest that a protein(s) other than PLC-gamma1 is functionally relevant for PAK targeting.
Shin
Kyung-Sun
KS
Department of Biochemistry, College of Medicine, Chungbuk National University, Cheongju, Korea.
Shin
Eun-Young
EY
Lee
Chan-Soo
CS
Quan
Song-Hua
SH
Woo
Kyung-Nam
KN
Soung
Nak-Kyun
NK
Kwak
Sahng-June
SJ
Kim
Seung Ryul
SR
Kim
Eung-Gook
EG
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D016716:PC12 Cells; D051966:Phospholipase C gamma; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport; D051381:Rats; D010738:Type C Phospholipases / Q000378:metabolism*; D054462:p21-Activated Kinases; D018909:src Homology Domains
D016222:Fibroblast Growth Factor 2; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D010738:Type C Phospholipases; D051966:Phospholipase C gamma