Premium
Overexpression of cellular activity and protein level of protein kinase F A /GSK‐3α correlates with human thyroid tumor cell dedifferentiation
Author(s) -
Lee TsongTze,
Ho YatSen,
Yu JauSong,
Yang ShiawDer
Publication year - 1995
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240580410
Subject(s) - protein kinase a , carcinogenesis , biology , gsk 3 , kinase , neoplastic transformation , thyroid , cancer research , microbiology and biotechnology , endocrinology , medicine , biochemistry , gene
Abstract Computer analysis of protein phosphorylation sites sequence revealed that transcriptional factors and viral oncoproteins are prime targets for regulation of proline‐directed protein phosphorylation, suggesting an association of the proline‐directed protein kinase (PDPK) family with neoplastic transformation and tumorigenesis. In this report, an immunoprecipitate activity assay of protein kinase F A /glycogen synthase kinase‐3α (kinase F A /GSK‐3α) (a member of the PDPK family) has been optimized for human thyroid tissue and used to demonstrate for the first time significantly increased ( P < 0.001) activity in thyroid carcinoma (24.2 ± 2.8 units/mg of protein) (n = 7), thyroid adenoma (14.5 ± 2.2 units/mg of protein) (n = 6), and thyroid hyperplasia (8.0 ± 2.4 units/mg of protein) (n = 5) when compared to five normal controls (4.1 ± 1.8 units/mg of protein). Immunoblotting analysis further revealed that increased activity of kinase F A /GSK‐3α in thyroid tumor cells is due to overexpression of protein level and cellular activity of kinase F A /GSK‐3α is involved in human thyroid tumor cell dedifferentiation, supporting an association of PDPK with neoplastic transformation and tumorigenesis. Since kinase F A /GSK‐3α may function as a possible regulator of transcription factors/protooncogenes, kinase F A /GSK‐3α may therefore play an important role in thyroid cell carcinogenesis, especially in its differentiation.