Characterization of a Mn sup 2+ -dependent membrane serine kinase that is activated by tyrosine phosphorylation

Conference · Mon Mar 11 04:00:00 EST 1991 · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)

OSTI ID:5370702

Singh, T J ^[1]

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1. Univ. of Waterloo, Ontario (Canada)

It is hypothesized that the insulin receptor (IR) tyrosine kinase may directly phosphorylate and activate one or more serine kinases. The identities of such serine kinases as well as their modes of activation are unclear. The authors have described a serine kinase from rat liver membranes that copurifies with the IR on wheat germ agglutinin (WGA)-sepharose. The kinase is activated after phosphorylation of the WGA-sepharose-purified fraction by casein kinase-1, casein kinase-2, or casein kinase-3. A tyrosine kinase, possibly IR tyrosine kinase, also participates in the activation process since a phosphotyrosine phosphatase inhibitor such as vanadate, p-nitrophenyl phosphate, or phosphotyrosine is required in reaction mixtures for activation to be observed. By contrast, phosphoserine and phosphothreonine do not support activation. The activated kinase can use IR {beta}-subunit, myelin basic protein (MBP), and histones as substrates. IR {beta}-subunit phosphorylation was stimulated by MBP, histones, and polylysine, and inhibited by heparin and poly(glu, tyr). The kinase prefers Mn{sup 2+} over Mg{sup 2+} as a metal cofactor.

• OSTI ID: 5370702
• Report Number(s): CONF-9104107--
• Conference Information: Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Journal Volume: 5:4
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINO ACIDS
ANIMALS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
DIGESTIVE SYSTEM
ELEMENTS
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
GLANDS
HYDROXY ACIDS
LIVER
MAMMALS
MANGANESE
MEMBRANES
METABOLISM
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
PROTEINS
RATS
RODENTS
SUBSTRATES
TRANSFERASES
TRANSITION ELEMENTS
TYROSINE
VERTEBRATES