Invasive human pituitary tumors express a point-mutated alpha-protein kinase-C.
J Clin Endocrinol Metab
; 77(5): 1125-9, 1993 Nov.
Article
em En
| MEDLINE
| ID: mdl-8077302
ABSTRACT
Protein kinase-C (PKC) is a ubiquitous eukaryotic kinase that plays a key role in transmembrane signaling and influences important cellular processes, such as proliferation. Increases in its activity and expression have been demonstrated in adenomatous human pituitaries, with protein expression being the highest in invasive tumors (1). Moreover, in these same invasive tumors, the mean increase in expression (8.9-fold) does not correlate with the mean increase in activity (2.6-fold), suggesting a dysfunction in PKC in these tumors. Here, we show that the PKC alpha-isoform (alpha PKC) is overexpressed in human pituitary tumors. The complete sequencing of the PKC cDNA from four invasive tumors has revealed a point mutation that is absent in the noninvasive tumors analyzed. The point mutation is located at position 294 of the protein, in the V3 region, leading to a substitution of a negatively charged aspartic acid by an apolar glycine. Thus, not only is alpha PKC overexpressed in human pituitary tumors, but it is also structurally altered in the invasive subpopulation of these tumors.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Hipofisárias
/
Proteína Quinase C
/
Mutação Puntual
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Clin Endocrinol Metab
Ano de publicação:
1993
Tipo de documento:
Article
País de afiliação:
França