Publication Date:
1992-08-28
Description:
Extracellular signals that promote cell growth activate cascades of protein kinases. The kinases are dephosphorylated and deactivated by a single type-2A protein phosphatase. The catalytic subunit of type-2A protein phosphatase was phosphorylated by tyrosine-specific protein kinases. Phosphorylation was enhanced in the presence of the phosphatase inhibitor okadaic acid, consistent with an autodephosphorylation reaction. More than 90% of the activity of phosphatase 2A was lost when thioadenosine triphosphate was used to produce a thiophosphorylated protein resistant to autodephosphorylation. Phosphorylation in vitro occurred exclusively on Tyr307. Phosphorylation was catalyzed by p60v-src, p56lck, epidermal growth factor receptors, and insulin receptors. Transient deactivation of phosphatase 2A might enhance transmission of cellular signals through kinase cascades within cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, J -- Martin, B L -- Brautigan, D L -- New York, N.Y. -- Science. 1992 Aug 28;257(5074):1261-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Biology and Medicine, Brown University, Providence, RI 02912.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1325671" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Ethers, Cyclic/pharmacology
;
Gene Expression Regulation/drug effects/*physiology
;
Humans
;
In Vitro Techniques
;
Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
;
Okadaic Acid
;
Oncogene Protein pp60(v-src)/pharmacology
;
Phosphoprotein Phosphatases/antagonists & inhibitors/*metabolism
;
Phosphorylation/drug effects
;
Protein Phosphatase 2
;
Protein-Tyrosine Kinases/physiology
;
Rabbits
;
Receptor, Epidermal Growth Factor/physiology
;
Receptor, Insulin/physiology
;
Thionucleotides/pharmacology
;
Tyrosine/*metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
