Sequence of the human glycogen-associated regulatory subunit of type 1 protein phosphatase and analysis of its coding region and mRNA level in muscle from patients with NIDDM.

Abstract

Impaired insulin-stimulated glycogen synthesis of peripheral tissues is a characteristic feature of many patients with non-insulin-dependent diabetes mellitus (NIDDM) and their first-degree relatives with normal glucose tolerance, suggesting putative inherited defects in this metabolic pathway. In previous studies, we have failed to reveal mutations in the coding regions of the muscle-specific glycogen synthase gene and the three genes that encode the catalytic subunits of protein phosphatase 1 (PP1) as frequent causes of insulin resistance. Because the glycogen-associated regulatory subunit of protein phosphatase 1 (PP1 G-subunit) plays a key role in the insulin stimulation of glycogen synthesis and the activity of PP1 is decreased in insulin-resistant subjects, we have now cloned the human G-subunit cDNA to search for abnormalities in the corresponding gene (designated PPP1R3 in the human genome nomenclature) in patients with NIDDM. The human cDNA was isolated from a skeletal muscle cDNA library and was found to encode a 126-kDa protein, which shows 73% amino acid identity to the rabbit PP1 G-subunit. The human G-subunit cDNA from 30 insulin-resistant NIDDM patients was analyzed for genetic variations in the G-subunit by using single-stranded conformation polymorphism (SSCP) scanning of reversely transcribed mRNA. One variant SSCP profile was detected in the region encoding the COOH-terminal part of the PP1 G-subunit in only one NIDDM patient, and subsequent nucleotide sequencing showed a C to A transversion on one allele at base position 2792. This change predicts an amino acid substitution from alanine to glutamic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

• Authors: Y H Chen, L Hansen, M X Chen, C Bjørbaek, H Vestergaard, T Hansen, P T Cohen, O Pedersen
• Journal: Diabetes (Diabetes) Vol. 43 Issue 10 Pg. 1234-41 (Oct 1994) ISSN: 0012-1797 [Print] United States
• PMID: 7926294 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA Primers
• Macromolecular Substances
• RNA, Messenger
• Glycogen
• Phosphoprotein Phosphatases
• Protein Phosphatase 1
• Glucose

Topics

• Amino Acid Sequence
• Animals
• Base Sequence
• DNA Primers
• Diabetes Mellitus, Type 2 (enzymology, genetics)
• Female
• Glucose (metabolism)
• Glycogen (metabolism)
• Humans
• Macromolecular Substances
• Male
• Middle Aged
• Molecular Sequence Data
• Muscles (metabolism)
• Phosphoprotein Phosphatases (genetics)
• Polymerase Chain Reaction
• Polymorphism, Genetic
• Protein Phosphatase 1
• RNA, Messenger (metabolism)
• Rabbits
• Reference Values
• Sequence Homology, Amino Acid