Hsp90 (heat shock protein 90) is an ATP-dependent molecular chaperone regulated by collaborating proteins called cochaperones. This machinery is involved in the conformational activation of client proteins like signaling kinases, transcription factors, or ribonucleoproteins (RNP) such as telomerase. TPR (TetratricoPeptide Repeat)-containing protein associated with Hsp90 (Tah1) and protein interacting with Hsp90 (Pih1) have been identified in Saccharomyces cerevisiae as two Hsp90 cochaperones involved in chromatin remodeling complexes and small nucleolar RNP maturation.
View Article and Find Full Text PDFGlutamine:fructose-6-phosphate amidotransferase (Gfat) catalyzes the first and rate-limiting step in the hexosamine biosynthetic pathway. The increasing amount of evidence that links excess hexosamine biosynthesis with pathogenic complications of type II diabetes highlights the need to understand the regulation of Gfat. Previous studies showed that eukaryotic Gfat is subjected to feedback inhibition by UDP-N-acetyl-d-glucosamine (UDP-GlcNAc) and to phosphorylation by cAMP-activated protein kinase A (PKA).
View Article and Find Full Text PDFBiochem Biophys Res Commun
October 2002
In eukaryotes, the coordinated progress of the various cellular tasks along with the assembly of adapted cytoskeletal networks requires a tight regulation of the interactions between microtubules and their associated proteins. Polyglutamylation is the major post-translational modification of neuronal tubulin. Due to its oligomeric structure, polyglutamylation can serve as a potentiometer to modulate binding of diverse MAPs.
View Article and Find Full Text PDFIron regulatory proteins (IRPs) control iron metabolism by specifically interacting with iron-responsive elements (IREs) on mRNAs. Nitric oxide (NO) converts IRP-1 from a [4Fe-4S] aconitase to a trans-regulatory protein through Fe-S cluster disassembly. Here, we have focused on the fate of IRE binding IRP1 from murine macrophages when NO flux stops.
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