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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1996-6-13
pubmed:abstractText
Among 11 isoforms of protein kinase C (PKC), we previously reported that the eta isoform of PKC plays a crucial role in mediating differentiation of keratinocytes. Activation of PKC is associated with its intracellular translocation from the cytoplasm to the plasma membrane, followed by down-regulation through proteolytic cleavage of the PKC molecules. In the present study, we demonstrated that the eta isoform of PKC is unique in that it is not translocated nor down-regulated upon stimulation. The level of the eta isoform, assayed by immunoblotting, remained unchanged during the first 12 h and then increased slightly up to 24 h when treated with tumor promoters or activators of PKC in constitutively expressing normal human keratinocytes. The activity of the eta isoform also remained unchanged after the 12-O-tetradecanoyl-phorbol-13-acetate treatment, as judged by binding ATP analog, autophosphorylation, and phosphorylation of an exogenous substrate. The alpha isoform of PKC, however, was rapidly down-regulated and was undetectable by 6 h after the treatment. These observations were further confirmed by immunohistochemical staining of normal human keratinocytes and transiently expressing COS1 cells. In addition, although the alpha isoform rapidly translocated to the plasma membrane, the eta isoform remained in the cytoplasm.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-202X
pubmed:author
pubmed:issnType
Print
pubmed:volume
106
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
790-4
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Absence of down-regulation and translocation of the eta isoform of protein kinase C in normal human keratinocytes.
pubmed:affiliation
Department of Cancer Cell Research, Institute of Medical Science, University of Tokyo, Japan.
pubmed:publicationType
Journal Article