Vanitha Thulasiraman

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The heme-regulated kinase of the alpha subunit of eukaryotic initiation factor 2 (HRI) is activated in rabbit reticulocyte lysate (RRL) in response to a number of environmental conditions, including heme deficiency, heat shock, and oxidative stress. Activation of HRI causes an arrest of initiation of protein synthesis. Recently, we have demonstrated that(More)
Renaturation of thermally denatured firefly luciferase in rabbit reticulocyte lysate (RRL) requires hsp90, hsc70, and other as yet unidentified RRL components [Schumacher, R.J., et al. (1994) J. Biol. Chem. 269, 9493-9499]. Benzoquinonoid ansamycins (BAs) have recently been shown to specifically bind hsp90 and inhibit its function. In this report, we(More)
To examine the biochemical mechanism by which hsp90 exerts its essential positive function on certain signal transduction proteins, we characterized the effects of molybdate and geldanamycin on hsp90 function and structure. Molybdate inhibited hsp90-mediated p56lck biogenesis and luciferase renaturation while enforcing salt-stable interactions with these(More)
The heme-regulated eIF-2alpha kinase (HRI) is activated not only in heme-deficient rabbit reticulocyte lysates (RRL), but also in hemin-supplemented RRL treated with heat-shock, N-ethylmaleimide (MalNEt) or heavy metal ions. We have demonstrated previously that heat-shock proteins, Hsp90, Hsp70 and FKBP52, are associated with HRI in RRL; the association of(More)
The role of the heat-shock cognate protein, Hsc70, in regulating the activity of the heme-regulated eIF-2alpha kinase (HRI) in hemin-supplemented rabbit reticulocyte lysate (RRL) in response to heat and oxidative stress was examined and compared with the effect of Hsc70 on HRI activation in response to heme deficiency. Hsc70 suppressed eIF-2alpha(More)
The ability of two high-affinity Hsc70-binding peptides [FYQLALT (peptide-Phi) and NIVRKKK (peptide-K)] to differentially inhibit Hsc70-dependent processes in rabbit reticulocyte lysate (RRL) was examined. Both peptide-Phi and peptide-K inhibited chaperone-dependent renaturation of luciferase in RRL. Peptide-Phi, but not peptide-K, blocked(More)
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