Involvement of Src in the vitamin D signaling in human keratinocytes.
1,25-dihydroxyvitamin D3 (VD) is a modulator of growth and differentiation of many cell types, including keratinocytes. We have recently shown in cultured keratinocytes that VD induces tyrosine phosphorylation of proteins involved in signal transduction, such as Shc. In an attempt to identify VD-responsive tyrosine kinases, we studied the effects of VD on the activity of the nonreceptor tyrosine kinase Src. Although VD did not stimulate Src activity in keratinocytes cultured in standard media containing 0.15 mM calcium, preincubation of the cells with 1.8 mM Ca2+ caused a rapid activation of Src in response to VD (10(-8)-10(-7) M). Elevation of calcium concentration alone caused an increase in Src activity as well, but the peak of Src activity was delayed (60 min vs. 15 min) and approximately 2-fold lower in comparison with VD-treated cells. VD treatment also induced tyrosine dephosphorylation of Src and a formation of an Src-Shc-Grb2 complex. Taken together, these findings imply that Src is involved in VD signaling in keratinocytes.
Gniadecki
R
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Department of Dermatological Research, Leo Pharmaceutical Products, Ballerup, Denmark.
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D002117:Calcitriol / Q000378:metabolism* / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D051380:GRB2 Adaptor Protein; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction / Q000187:drug effects; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D046911:Macromolecular Substances; D011506:Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine; D019061:src-Family Kinases; D002117:Calcitriol; D002118:Calcium