BIO202H5 Lecture Notes - Lecture 51: Heat Shock Factor, Hyperthermia, Heat Shock Protein
Document Summary
Temperature increase causes increase in standard (smr) and maximal (mmr) metabolic rates in poikilotherms. At pejus temperature (tp), mmr starts to decline as the organisms fails to meet metabolic demands: at this point, the mmr cannot be increased any more. At critical temperatures (tc), smr=mmr and the organism cannot generate enough oxygen and energy: you ca(cid:374)"t do (cid:373)uch other tha(cid:374) survive, the maximum and minimum metabolic rates than an organism can maintain. When exposed to extreme temperatures, many cells undergo heat shock response. Heat stress causes hsf (heat shock factor) to move into the nucleus and bind to the promoter of genes with heat shock elements, increases hsp (heat shock protein) gene transcription. High heat demand causes dissociation of the hsf-hsp70 complex, allowing it to bind to the promoter regions of heat shock gene elements. Hsp70 evolved to fight antigens and is involved in the immune system.
