title: Phospholipase C-gamma1 is required for subculture-induced terminal differentiation of normal human oral keratinocytes.
abstract: 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.
authors.affiliation: Department of Oral Biochemistry, Dental Research Institute, IBEC, and BK21 HLS, Seoul National University, College of Dentistry, Seoul, Korea.
authors.forename: Ju-Eun
authors.initials: JE
authors.lastname: Oh
authors.forename: Joong-Ki
authors.initials: JK
authors.lastname: Kook
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Park
authors.forename: Gene
authors.initials: G
authors.lastname: Lee
authors.forename: Byoung-Moo
authors.initials: BM
authors.lastname: Seo
authors.forename: Byung-Moo
authors.initials: BM
authors.lastname: Min
mesh_terms: 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*
chemical_list: D011498:Protein Precursors; C032253:involucrin; D011503:Transglutaminases; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D002118:Calcium