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

Journal Article · Tue Feb 20 00:00:00 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), Vol. 29:7; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

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