ABSTRACT
Plant Rac proteins belong to an important group of signal switches anchoring on membranes, involved in various physiological processes including cell polar growth, synthesis of secondary wall, resistance response and hormone signaling. In the attempt to elucidate the molecular mechanism of initiation and elongation of cotton fiber, two cotton Rac protein genes, designated as GhRacA and GhRacB, were amplified from elongating fibers and cloned. It was demonstrated that, the cDNA of GhRacA contained 959 bp and encoded a putative polypepetide of 211 aa, while GhRacB was 920 bp in length, encoding a predicted protein of 195 aa. These two cotton Rac proteins, GhRacA and GhRacB, contained conserved regions involved in GTP/GDP binding and activation, an effector region and a polybasic region. A conserved prenylation site CSIL was found in GhRacB, while no apparent prenylation site was discovered in GhRacA. Sequence comparisons showed that GhRacA and GhRacB were two novel Rac proteins from cotton. The expression patterns of GhRacA and GhRacB was analyzed by RT-PCR. It was demonstrated that these two Rac protein genes were both expressed in root, hypocotyls, stem, leaf and fibers, and the highest level of transcripts was to accumulate in the fibers at the stage of initiation and elongation, suggesting that the two Rac genes, GhRacA and GhRacB, might play an important role in the early stage of fiber development.
Subject(s)
Expressed Sequence Tags , Genes, Plant , Gossypium/genetics , Amino Acid Sequence , Base Sequence , Cloning, Molecular , Conserved Sequence , Cotton Fiber , DNA, Complementary/analysis , DNA, Complementary/genetics , Gene Expression Regulation, Plant , Gossypium/growth & development , Gossypium/metabolism , Molecular Sequence Data , Phylogeny , Sequence Alignment , Sequence Homology, Amino AcidABSTRACT
Objective: To investigate whether insulin stimulates the translocation of glucose transporter-4 (GLUT4) and glucose uptak e in ischemic myocardium. Methods: Plasma concentration of gluc ose, lactate, free fatty acid and insulin were determined by autoanalyser, and G LUT4 was studied by Western blotting analysis. Results: Insulin increased GLUT4 significantly in sarcolemma of ischemic myocardium ［(25±4)% vs (40±6)%］, and GLUT4 content in intracellular membrane decreased proporti onally. The glucose uptake increased significantly in insulin-ischemic myocardi um. The uptake of insulin-ischemic myocardium was almost 2 times that of ischem ic myocardium. Conclusion: Insulin stimulation results in GLUT4 translocation and increases glucose uptake in ischemic myocardium. When myocardi al ischemia occurs, insulin is helpful in increasing myocardial glucose uptake a nd utilization.
ABSTRACT
Objective: To investigate whether insulin stimulates the translocation of glucose transporter-4 (GLUT4) and glucose uptak e in ischemic myocardium. Methods: Plasma concentration of gluc ose, lactate, free fatty acid and insulin were determined by autoanalyser, and G LUT4 was studied by Western blotting analysis. Results: Insulin increased GLUT4 significantly in sarcolemma of ischemic myocardium ［(25±4)% vs (40±6)%］, and GLUT4 content in intracellular membrane decreased proporti onally. The glucose uptake increased significantly in insulin-ischemic myocardi um. The uptake of insulin-ischemic myocardium was almost 2 times that of ischem ic myocardium. Conclusion: Insulin stimulation results in GLUT4 translocation and increases glucose uptake in ischemic myocardium. When myocardi al ischemia occurs, insulin is helpful in increasing myocardial glucose uptake a nd utilization.
