Threonine 1336 of the human insulin receptor is a major target for phosphorylation by protein kinase C

Journal Article · Tue Feb 20 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00459a020· OSTI ID:6897378

Lewis, R E; Cao, Lin; Perregaux, D; Czech, M P ^[1]

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1. Univ. of Massachusetts Medical Center, Worcester (USA)

The ability of tumor-promoting phorbol diesters to inhibit both insulin receptor tyrosine kinase activity and its intracellular signaling correlates with the phosphorylation of the insulin receptor {beta} subunit on serine and threonine residues. In the present studies, mouse 3T3 fibroblasts transfected with a human insulin receptor cDNA and expressing greater than one million of these receptors per cell were labeled with ({sup 32}P)phosphate and treated with or without 100 nM 4{beta}-phorbol 12{beta}-myristate 13{alpha}-acetate (PMA). Phosphorylated insulin receptors were immunoprecipitated and digested with trypsin. Alternatively, insulin receptors affinity purified from human term placenta were phosphorylated by protein kinase C prior to trypsin digestion of the {sup 32}P-labeled {beta} subunit. Analysis of the tryptic phosphopeptides from both the in vivo and in vitro labeled receptors by reversed-phase HPLC and two-dimensional thin-layer separation revealed that PMA and protein kinase C enhanced the phosphorylation of a peptide with identical chromatographic properties. Comparison of these data with the known, deduced receptor sequence suggested that the receptor-derived tryptic phosphopeptide might be Ile-Leu-Thr(P)-Leu-Pro-Arg. The phosphorylation site corresponds to threonine 1336 in the human insulin receptor {beta} subunit. This threonine, which resides in a receptor domain also containing tyrosine phosphorylation sites, is located eight amino acids from the carboxyl terminus of the {beta} subunit and may play a role in the protein kinase C induced inhibition of insulin receptor tyrosine kinase activity.

• OSTI ID: 6897378
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:7; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACID SEQUENCE
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHROMATOGRAPHY
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
DNA
ENZYMES
FIBROBLASTS
HORMONES
HYDROXY ACIDS
INSULIN
ISOTOPES
LIGHT NUCLEI
LIQUID COLUMN CHROMATOGRAPHY
MAMMALS
MAN
MEMBRANE PROTEINS
MICE
MOLECULAR STRUCTURE
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
PRIMATES
PROTEINS
RADIOASSAY
RADIOISOTOPES
RECEPTORS
RECOMBINANT DNA
RODENTS
SEPARATION PROCESSES
SOMATIC CELLS
THIN-LAYER CHROMATOGRAPHY
THREONINE
TRANSFERASES
VERTEBRATES