Identification and characterization of the ligand-binding domain of insulin receptor by use of an anti-peptide antiserum against amino acid sequence 241-251 of the. alpha. subunit

Journal Article · Tue Jan 22 00:00:00 EST 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00217a016· OSTI ID:5451915

Yip, C C ^[1]; Grunfeld, C ^[2]; Goldfine, I D ^[3]

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1. Univ. of Toronto, Ontario (Canada)
2. Univ. of California, San Francisco (USA) VA Medical Center, San Francisco, CA (USA)
3. Mount Zion Hospital and Medical Center, San Francisco, CA (USA)

The authors previously reported that a 23-kDa receptor proteolytic fragment containing an insulin-binding site was localized within residues 205-316 in the cysteine-rich region of the insulin receptor {alpha} subunit and postulated that sequence 241-251 plays a major role in insulin binding. In the present study, they have used an antiserum raised against a synthetic peptide containing sequence 241-251 to test this postulate and to study the role of sequence 241-251 in insulin binding. The antiserum immunoprecipitated the 23-kDa fragment, confirming their sequence assignment of this fragment. It also immunoprecipitated the intact {alpha} subunit of the insulin receptor that had been denatured by reduction and alkylation. However, sequence 241-251 in the native receptor was inaccessible to the antiserum since the antiserum did not block ({sup 125}I)iodoinsulin binding and did not precipitate either photoaffinity-labeled insulin receptors or insulin receptors labeled with {sup 125}I. However, using a radioactive photoaffinity probe (({sup 125}I)-AZAP-insulin) that allows cleavage and removal of insulin after photolabeling. They found that sequence 241-251 became accessible to the antiserum after removal of insulin. They conclude therefore that sequence 241-251 forms part of the insulin-binding domain of the insulin receptor and that the binding of insulin to the receptor induces a conformational change that allows exposure of this domain after removal of insulin. Such a conformational change may play a role in activation of the receptor and transmembrane signaling.

• OSTI ID: 5451915
• Journal Information: Biochemistry; (United States), Vol. 30:3; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
INSULIN
RADIORECEPTOR ASSAY
RECEPTORS
CONFORMATIONAL CHANGES
AMINO ACID SEQUENCE
IODINE 125
LIGANDS
MOLECULAR STRUCTURE
BETA DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PROTEINS
RADIOISOTOPES
TRACER TECHNIQUES
550201* - Biochemistry- Tracer Techniques