Solubilized placental membrane protein inhibits insulin receptor tyrosine kinase activity
Regulation of insulin receptor (IR) tyrosine kinase (TK) activity may be important in modulating insulin action. Utilizing an assay which measures IR phosphorylation of angiotensin II (AII), the authors investigated whether fractions of TX-100 solubilized human placental membranes inhibited IR dependent AII phosphorylation. Autophosphorylated IR was incubated with membrane fractions before the addition of AII, and kinase inhibition measured by the loss of TSP incorporated in AII. An inhibitory activity was detected which was dose, time, and temperature dependent. The inhibitor was purified 200-fold by sequential chromatography on wheat germ agglutinin, DEAE, and hydroxyapatite. This inhibitory activity was found to correlate with an 80 KD protein which was electroeluted from preparative slab gels and rabbit antiserum raised. Incubation of membrane fractions with antiserum before the IRTK assay immunoprecipitated the inhibitor. Protein immunoblots of crude or purified fractions revealed only the 80 KD protein. Since IR autophosphorylation is crucial to IRTK activity, the authors investigated the state of IR autophosphorylation after treatment with inhibitor; no change was detected by phosphoamino acid analysis.
- Research Organization:
- Merck Research Labs., Rahway, NJ
- OSTI ID:
- 6358943
- Report Number(s):
- CONF-870644-; TRN: 87-028707
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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ANGIOTENSIN
PHOSPHORYLATION
INSULIN
RECEPTORS
PHOSPHOTRANSFERASES
ENZYME ACTIVITY
BIOASSAY
CELL MEMBRANES
DOSE-RESPONSE RELATIONSHIPS
PHOSPHORUS 32
PLACENTA
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRACER TECHNIQUES
TYROSINE
AMINO ACIDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DRUGS
ENZYMES
FETAL MEMBRANES
GLOBULINS
HORMONES
HYDROXY ACIDS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MEMBRANES
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PROTEINS
RADIOISOTOPES
TRANSFERASES
VASOCONSTRICTORS
550201* - Biochemistry- Tracer Techniques