We identified a heterozygous missense mutation that substituted aspartic acid (GAC) for alanine (GCC) at codon 1048 of the insulin receptor gene in a patient who displayed typical symptoms of Type A syndrome of insulin resistance. The proband's mother and younger brother were also found to be heterozygous for the mutation. We constructed the identified mutant insulin receptor cDNA by site-directed mutagenesis, transfected the mutant cDNA into COS 7 cells, and found that kinase activity of the mutant insulin receptors was markedly impaired. Ala1048 is located in the kinase domain of the insulin receptor β-subunit and is conserved in most of protein-tyrosine kinases. Besides, neighboring Glu1047 is invariant in all protein kinases and is thought to be involved in interaction with ATP. Photoaffinity labeling of the mutant insulin receptor with ATP analogue, 8-azido (α-32P)ATP was not influenced by the mutation, suggesting that the mutation did not inhibit ATP binding but possibly interfered with subsequent phosphoryl transfer. Insulin-stimulated phosphorylation of exogenous substrate by partially purified insulin receptors prepared from COS 7 cells that were cotransfected with wild-type and mutant insulin receptor cDNAs was markedly impaired, whereas autophosphorylation was decreased by ∼ 50% of wild-type receptors. These results indicated that the identified heterozygous substitution of Asp for Ala1048 in insulin receptor was responsible for insulin resistance of this patient.
Skip Nav Destination
Article navigation
Original Articles|
December 01 1993
Ala1048→Asp Mutation in the Kinase Domain of Insulin Receptor Causes Defective Kinase Activity and Insulin Resistance
Tetsuro Haruta;
Tetsuro Haruta
First Department of Medicine, Toyama Medical and Pharmaceutical University
Sugitani, Toyama
Department of Medicine, Shiga University of Medical Science Ohtsu
Shiga
Division of Endocrinology and Metabolism, the Nagoya Second Red Cross Hospital
Nagoya, Japan
Search for other works by this author on:
Yasumitsu Takata;
Yasumitsu Takata
First Department of Medicine, Toyama Medical and Pharmaceutical University
Sugitani, Toyama
Department of Medicine, Shiga University of Medical Science Ohtsu
Shiga
Division of Endocrinology and Metabolism, the Nagoya Second Red Cross Hospital
Nagoya, Japan
Search for other works by this author on:
Masanori Iwanishi;
Masanori Iwanishi
First Department of Medicine, Toyama Medical and Pharmaceutical University
Sugitani, Toyama
Department of Medicine, Shiga University of Medical Science Ohtsu
Shiga
Division of Endocrinology and Metabolism, the Nagoya Second Red Cross Hospital
Nagoya, Japan
Search for other works by this author on:
Hiroshi Maegawa;
Hiroshi Maegawa
First Department of Medicine, Toyama Medical and Pharmaceutical University
Sugitani, Toyama
Department of Medicine, Shiga University of Medical Science Ohtsu
Shiga
Division of Endocrinology and Metabolism, the Nagoya Second Red Cross Hospital
Nagoya, Japan
Search for other works by this author on:
Takeshi Imamura;
Takeshi Imamura
First Department of Medicine, Toyama Medical and Pharmaceutical University
Sugitani, Toyama
Department of Medicine, Shiga University of Medical Science Ohtsu
Shiga
Division of Endocrinology and Metabolism, the Nagoya Second Red Cross Hospital
Nagoya, Japan
Search for other works by this author on:
Katsuya Egawa;
Katsuya Egawa
First Department of Medicine, Toyama Medical and Pharmaceutical University
Sugitani, Toyama
Department of Medicine, Shiga University of Medical Science Ohtsu
Shiga
Division of Endocrinology and Metabolism, the Nagoya Second Red Cross Hospital
Nagoya, Japan
Search for other works by this author on:
Takeharu Itazu;
Takeharu Itazu
First Department of Medicine, Toyama Medical and Pharmaceutical University
Sugitani, Toyama
Department of Medicine, Shiga University of Medical Science Ohtsu
Shiga
Division of Endocrinology and Metabolism, the Nagoya Second Red Cross Hospital
Nagoya, Japan
Search for other works by this author on:
Masashi Kobayashi
Masashi Kobayashi
First Department of Medicine, Toyama Medical and Pharmaceutical University
Sugitani, Toyama
Department of Medicine, Shiga University of Medical Science Ohtsu
Shiga
Division of Endocrinology and Metabolism, the Nagoya Second Red Cross Hospital
Nagoya, Japan
Search for other works by this author on:
Address correspondence and reprint requests to Dr. Masashi Kobayashi, First Department of Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Toyama, 930–01 Japan.
Diabetes 1993;42(12):1837–1844
Article history
Received:
August 17 1992
Revision Received:
July 22 1993
Accepted:
July 22 1993
PubMed:
8243830
Citation
Tetsuro Haruta, Yasumitsu Takata, Masanori Iwanishi, Hiroshi Maegawa, Takeshi Imamura, Katsuya Egawa, Takeharu Itazu, Masashi Kobayashi; Ala1048→Asp Mutation in the Kinase Domain of Insulin Receptor Causes Defective Kinase Activity and Insulin Resistance. Diabetes 1 December 1993; 42 (12): 1837–1844. https://doi.org/10.2337/diab.42.12.1837
Download citation file:
61
Views