Phospholipase C-gamma1 is required for calcium-induced keratinocyte differentiation.
Phospholipase C-gamma1 is the most abundant member of the phospholipase C family in keratinocytes and is induced by calcium. Phospholipase C-gamma1, therefore, may be involved in the signal transduction system leading to calcium regulation of keratinocyte differentiation. To test this hypothesis, expression of phospholipase C-gamma1 in human keratinocytes was blocked by transfecting cells with the antisense human phospholipase C-gamma1 cDNA construct. These cells demonstrated a dramatic reduction in phospholipase C-gamma1 protein level compared with the empty vector-transfected cells and a marked reduction in the mRNA and protein levels of the differentiation markers involucrin and transglutaminase following administration of calcium. Similarly, cotransfection of antisense phospholipase C-gamma1 constructs with a luciferase reporter vector containing involucrin or transglutaminase promoters led to a substantial reduction in calcium-stimulated involucrin and transglutaminase promoter activities. Similar results were seen following treatment with a specific phospholipase C inhibitor U73122. To determine whether phospholipase C-gamma1 regulated differentiation by controlling intracellular calcium, we examined the ability of antisense phospholipase C-gamma1 to block the calcium-induced rise in intracellular calcium and found that it could. These findings indicate that phospholipase C-gamma1 is a critical component of the signaling pathway mediating calcium regulation of keratinocyte differentiation via its mobilization of intracellular calcium.
Endocrine Unit, Veterans Affairs Medical Center, University of California, San Francisco, California 94121, USA. zjxie@itsa.ucsf.edu
Z
Z
Xie
D D
DD
Bikle
D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D016373:DNA, Antisense / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D015603:Keratinocytes / Q000201:enzymology / Q000378:metabolism*; D051966:Phospholipase C gamma; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism*
D016373:DNA, Antisense; D007527:Isoenzymes; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D002118:Calcium