A novel variant of glutamine - Fructose-6-phosphate amidotransferase-1 (GFAT1) mRNA is selectively expressed in striated muscle

被引:43
作者
DeHaven, JE
Robinson, KA
Nelson, BA
Buse, MG [1 ]
机构
[1] Med Univ S Carolina, Dept Med, Div Endocrinol Diabet & Med Genet, Charleston, SC 29425 USA
[2] Med Univ S Carolina, Dept Biochem & Mol Biol, Charleston, SC 29425 USA
关键词
D O I
10.2337/diabetes.50.11.2419
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Glutamine: fructose-6-phosphate amidotransferase (GFAT) is the rate-limiting enzyme of the hexosamine synthesis pathway. Products of this pathway have been implicated in insulin resistance and glucose toxicity. GFAT1 is ubiquitous, whereas GFAT2 is expressed mainly in the central nervous system. In the course of developing a competitive reverse transcriptase-polymerase chain reaction assay, we noted that GFAT1 cDNA from muscle but not from other tissues migrated as a doublet. Subsequent cloning and sequencing revealed two GFAT1 mRNAs in both mouse and human skeletal muscles. The novel GFAT1 mRNA (GFAT1Alt [muscle selective variant of GFAT1]) is likely a splice variant. It is identical to GFAT1 except for a 48 or 54 bp insert in the mouse and human, respectively, at nucleotide position 686 of the coding sequence, resulting in a 16 or 18 amino acid insert at position 229 of the protein. GFAT1Alt is the predominant GFAT1 mRNA in mouse hindlimb muscle, is weakly expressed in the heart, and is undetectable in the brain, liver, kidney, lung, intestine, spleen, and 3T3-L1 adipocytes. In humans, it is strongly expressed in skeletal muscle but not in the brain. GFAT1 and GFAT1Alt expressed by recombinant adenovirus infection in COS-7 cells displayed robust enzyme activity and kinetic differences. The apparent K-m of GFAT1Alt for fructose-6-phosphate was approximately twofold higher than that of GFAT1, whereas Ki for UDP-N-acetylglucosamine was approximately fivefold lower. Muscle insulin resistance is a hallmark and predictor of type 2 diabetes. Variations in the expression of GFAT isoforms in muscle may contribute to predisposition to insulin resistance.
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页码:2419 / 2424
页数:6
相关论文
共 27 条
[1]   Differential effects of GLUT1 or GLUT4 overexpression on hexosamine biosynthesis by muscles of transgenic mice [J].
Buse, MG ;
Robinson, KA ;
Marshall, BA ;
Mueckler, M .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1996, 271 (38) :23197-23202
[2]   Increased activity of the hexosamine synthesis pathway in muscles of insulin-resistant ob/ob mice [J].
Buse, MG ;
Robinson, KA ;
Gettys, TW ;
McMahon, EG ;
Gulve, EA .
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM, 1997, 272 (06) :E1080-E1088
[3]   Mechanism of hexosamine-induced insulin resistance in transgenic mice overexpressing glutamine:fructose-6-phosphate amidotransferase:: Decreased glucose transporter GLUT4 translocation and reversal by treatment with thiazolidinedione [J].
Cooksey, RC ;
Hebert, LF ;
Zhu, JH ;
Wofford, P ;
Garvey, WT ;
McClain, DA .
ENDOCRINOLOGY, 1999, 140 (03) :1151-1157
[4]   Hyperglycemia-induced mitochondrial superoxide overproduction activates the hexosamine pathway and induces plasminogen activator inhibitor-1 expression by increasing Sp1 glycosylation [J].
Du, XL ;
Edelstein, D ;
Rossetti, L ;
Fantus, IG ;
Goldberg, H ;
Ziyadeh, F ;
Wu, J ;
Brownlee, M .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2000, 97 (22) :12222-12226
[5]  
HAN IO, 1997, MOL CELL BIOL, V17, P2250
[6]   Dynamic O-linked glycosylation of nuclear and cytoskeletal proteins [J].
Hart, GW .
ANNUAL REVIEW OF BIOCHEMISTRY, 1997, 66 :315-335
[7]   The tissue concentration of UDP-N-acetylglucosamine modulates the stimulatory effect of insulin on skeletal muscle glucose uptake [J].
Hawkins, M ;
Angelov, I ;
Liu, R ;
Barzilai, N ;
Rossetti, L .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1997, 272 (08) :4889-4895
[8]   A simplified system for generating recombinant adenoviruses [J].
He, TC ;
Zhou, SB ;
da Costa, LT ;
Yu, J ;
Kinzler, KW ;
Vogelstein, B .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1998, 95 (05) :2509-2514
[9]   Overexpression of glutamine:fructose-6-phosphate amidotransferase in transgenic mice leads to insulin resistance [J].
Hebert, LF ;
Daniels, MC ;
Zhou, JX ;
Crook, ED ;
Turner, RL ;
Simmons, ST ;
Neidigh, JL ;
Zhu, JS ;
Baron, AD ;
McClain, DA .
JOURNAL OF CLINICAL INVESTIGATION, 1996, 98 (04) :930-936
[10]   FEEDBACK CONTROL OF SUGAR NUCLEOTIDE BIOSYNTHESIS IN LIVER [J].
KORNFELD, S ;
NEUFELD, EF ;
OBRIEN, PJ ;
KORNFELD, R .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1964, 52 (02) :371-&