PKCdelta clustering at the leading edge and mediating growth factor-enhanced, but not ecm-initiated, dermal fibroblast migration.
We have previously shown that the immobilized extracellular matrices (ECMs) initiate cell migration and soluble growth factors (GFs) further enhance ECM-initiated cell migration. GFs alone cannot initiate cell migration. To further investigate the specificity of the two signaling mechanisms, we focused on the protein kinase C (PKC) family genes in primary human dermal fibroblasts (DFs). We here show that platelet-derived growth factor-BB (PDGF-BB) strongly stimulates membrane translocation and leading edge clustering of protein kinase Cdelta (PKCdelta). In contrast, attachment to collagen matrix alone does not cause the translocation. Although the kinase function of PKCdelta is dispensable for initial membrane translocation, it is critical for its sustained presence at the cells's leading edge. Blockade of endogenous PKCdelta signaling with dominant-negative kinase-defective PKC (PKCdelta-KD) or PKCdelta-small interfering RNA (siRNA) completely inhibited PDGF-BB-stimulated DF migration. In contrast, neither PKCdelta-KD nor PKCdelta-siRNA affected collagen-induced initiation of DF migration. Overexpression of a constitutively activated PKCdelta (PKCdelta-R144/145A) partially mimics the effect of PDGF-BB. However, PKCdelta-KD, PKCdelta-siRNA, or PKCdelta-R144/145A does not affect PDGF-BB-stimulated activation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase1/2, or c-Jun N-terminal kinase. Instead, inhibition of PKCdelta blocks PDGF-BB-stimulated activation of signal transducer and activator of transcription 3 (Stat3). This study unveiled the specificity of PKCdelta in the control of DF migration.
The Department of Dermatology and the Norris Comprehensive Cancer Center, The University of Southern California Keck School of Medicine, Los Angeles, California, USA.
Jianhua
J
Fan
Shengxi
S
Guan
Chieh-Fang
CF
Cheng
Michele
M
Cho
Joshua W
JW
Fields
Mei
M
Chen
Mitchell F
MF
Denning
David T
DT
Woodley
Wei
W
Li
D000077214:Becaplermin; D002462:Cell Membrane / Q000187:drug effects* / Q000201:enzymology; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D016764:Cell Polarity; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009154:Mutation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D051745:Protein Kinase C-delta / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D021381:Protein Transport; D020574:Proto-Oncogene Proteins c-sis; D034622:RNA Interference; D050796:STAT3 Transcription Factor / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D000077214:Becaplermin; D051745:Protein Kinase C-delta; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases