Heat Shock Protein (HSP)

Abstract

Synonyms HSP Definition Eukaryotes respond to heat shock and other forms of environmental stress by inducing synthesis of heat-shock proteins (HSP). HSPs act, e.g., as chaper-onins, a subclass of ▶chaperones with ATPase activity, maintaining the correct 3-D structure of large protein complexes. For example, the hsp90 proteins are a group of HSPs with an average molecular weight of 90 Kd. The precise function of hsp90 is unclear. The protein is associated with steroid hormone receptors, tyrosine kinases, eIF2alpha kinase, actin and tubulin. ▶Glucocorticoids ▶Protein Trafficking and Quality Control ▶Chaperones Helicases Group of evolutionary highly conserved enzymes involved in structural modulation of nucleic acids. Specific for either DNA or RNA they unwind double-stranded regions by dissociating paired purin–pyrimidin bases. A helicase domain is essential for enzymatic activity that is dependent on energy generated from nucleoside-triphosphate hydrolysis. RNA helicases are important during transcription, splicing, translation, and degradation of eukaryotic RNA.