title: Non-compensating roles between Nckalpha and Nckbeta in PDGF-BB signaling to promote human dermal fibroblast migration.
abstract: Platelet-derived growth factor BB (PDGF-BB) is a Food and Drug Administration (FDA)-approved growth factor, acting as a mitogen and motogen of dermal fibroblasts (DFs), for skin wound healing. The two closely related SH2/SH3 adapter proteins, Nckalpha and Nckbeta, connect PDGF-BB signaling to the actin cytoskeleton and cell motility. The mechanism has not been fully understood. In this study, we investigated, side by side, the roles of Nckalpha and Nckbeta in PDGF-BB-stimulated DF migration. We found that cells expressing the PDGFRbeta-Y751F mutant (preventing Nckalpha binding) or PDGFRbeta-Y1009F mutant (preventing Nckbeta binding), DF cells isolated from Nckalpha- or Nckbeta-knockout mice, and primary human DF cells with RNA interference (RNAi) knockdown of the endogenous Nckalpha or Nckbeta all failed to migrate in response to PDGF-BB. Overexpression of the middle SH3 domain of Nckalpha or Nckbeta alone in human DFs also blocked PDGF-BB-induced cell migration. However, neither Nckalpha nor Nckbeta was required for the activation of the PDGF receptor, p21-activated protein kinase (Pak1), AKT, extracellular signal-regulated kinase (ERK) 1/2, or p38MAP by PDGF-BB. Although PDGF-BB stimulated the membrane translocation of both Nckalpha and Nckbeta, Nckalpha appeared to mediate Cdc42 signaling for filopodium formation, whereas Nckbeta mediated Rho signaling to induce stress fibers. Thus, this study has elucidated the independent roles and mechanisms of action of Nckalpha and Nckbeta in DF migration, which is critical for wound healing.
authors.affiliation: Department of Dermatology and USC-Norris Comprehensive Cancer Center, Keck School of Medicine, The University of Southern California, Los Angeles, California 90033, USA.
authors.forename: Shengxi
authors.initials: S
authors.lastname: Guan
authors.forename: Jianhua
authors.initials: J
authors.lastname: Fan
authors.forename: Arum
authors.initials: A
authors.lastname: Han
authors.forename: Mei
authors.initials: M
authors.lastname: Chen
authors.forename: David T
authors.initials: DT
authors.lastname: Woodley
authors.forename: Wei
authors.initials: W
authors.lastname: Li
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology*; D000818:Animals; D000077214:Becaplermin; D002465:Cell Movement; D005347:Fibroblasts / Q000187:drug effects / Q000502:physiology; D006801:Humans; D051379:Mice; D015513:Oncogene Proteins / Q000502:physiology*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D020574:Proto-Oncogene Proteins c-sis; D015398:Signal Transduction / Q000502:physiology*; D012867:Skin / Q000166:cytology; D014945:Wound Healing; D020764:cdc42 GTP-Binding Protein / Q000502:physiology; D020742:rhoA GTP-Binding Protein / Q000502:physiology; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C485544:NCK2 protein, human; C078332:Nck protein; C117758:Nck2 protein, mouse; D015513:Oncogene Proteins; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D020764:cdc42 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein