Phospholipase C-gamma1 is required for subculture-induced terminal differentiation of normal human oral keratinocytes.
Serial subculture of primary normal human oral keratinocytes (NHOKs) to the post-mitotic stage induces terminal differentiation, which is in part linked to elevated levels of phospholipase C (PLC)-gamma1. Therefore, PLC-gamma1 may be involved in the signal transduction system that leads to the calcium regulation of subculture-induced keratinocyte differentiation. To test this hypothesis, the expression of PLC-gamma1 in primary NHOKs was blocked by transfecting cells with the antisense PLC-gamma1 cDNA construct. These cells demonstrated dramatic reductions in PLC-gamma1 protein and in the differentiation markers involucrin and transglutaminase following calcium exposure and an increase (15-20%) in in vitro life span versus empty vector-transfected cells. In addition, we established the ability of antisense PLC-gamma1 to block the serial subculture-induced rise in intracellular calcium. Similar observations were made following treatment with the specific PLC inhibitor U73122. These results indicate that the terminal differentiation of NHOKs by serial subculture is associated with PLC-gamma1, which mediates calcium regulation by mobilizing intracellular calcium.
Oh
Ju-Eun
JE
Department of Oral Biochemistry, Dental Research Institute, IBEC, and BK21 HLS, Seoul National University, College of Dentistry, Seoul, Korea.
Kook
Joong-Ki
JK
Park
Kyung-Hee
KH
Lee
Gene
G
Seo
Byoung-Moo
BM
Min
Byung-Moo
BM
D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism*; D009061:Mouth Mucosa / Q000378:metabolism; D051966:Phospholipase C gamma; D011401:Promoter Regions, Genetic; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D011503:Transglutaminases / Q000235:genetics / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism*
D011498:Protein Precursors; C032253:involucrin; D011503:Transglutaminases; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D002118:Calcium