Heat stress induces tyrosine phosphorylation/activation of kinase Fa/GSK-3α (a human carcinoma dedifferentiation modulator) in A431 cells

✍ Scribed by Shiaw-Der Yang; Shan-Chih Lee; Hsiou-Chen Chang

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 220 KB
• Volume: 66
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/(sici)1097-4644(19970701)66:1<16::aid-jcb3>3.0.co;2-0

✦ Synopsis

Exposure of A431 cells to a rapid temperature increase from 37°to 46°C could induce an increased expression (,200% of control) and tyrosine phosphorylation/activation (,300% of control) of protein kinase FA/ glycogen synthase kinase-3a (kinase FA/GSK-3a) in a time-dependent manner, as demonstrated by an anti-kinase FA/GSK-3a immunoprecipitate kinase assay and by immunoblotting analysis with anti-kinase FA/GSK-3a and antiphosphotyrosine antibodies. The heat induction on the increased expression of kinase FA/GSK-3a could be blocked by actinomycin D but not by genistein. In contrast, the heat induction on tyrosine phosphorylation/activation of kinase FA/GSK-3a could be blocked by genistein or protein tyrosine phosphatase, indicating that heat stress induces a dual control mechanism, namely, protein expression and subsequent tyrosine phosphorylation to cause cellular activation of kinase FA/GSK-3a. Taken together, the results provide initial evidence that kinase FA/GSK-3a represents a newly described heat stress-inducible protein subjected to tyrosine phosphorylation/activation, representing a new mode of signal transduction for the regulation of this human carcinoma dedifferentiation modulator and a new mode of heat induction on cascade activation of a protein kinase.