Stress relief protein modulation by calnexin.
Oxygen free radical (OFR)-mediated oxidative stress in myocardial cells following ischemia could damage unit membrane and macromolecules such as nucleic acids (DNA). It is being reported that under this condition these cells produce antioxidants and heat shock proteins (HSP 70). It is implied that this family of proteins could function as a "molecular chaperone" in the cell and hence has to be transported to various target sites. This process is comparable to the induction of oxygen free radicals in melanocytes and its response, melanin production following UV light exposure stress. Lamp-1, trp-1 and tyrosinase are melanosomal-associated stress relief proteins which are involved in the production of melanin in the subcellular organelle, melanosomes. UV exposure studies as well as gene transfection studies and antisense hybridization in human melanoma cells clearly indicated an increase and marked coordinated interaction of all these stress relief proteins in melanogenesis. These proteins are synthesized in the endoplasmic reticulum and have to undergo posttranslation modification, sorting and posting to their respective target sites. We simultaneously identified and characterized an ER resident protein, calnexin. It became the potential candidate for "chaperoning" these proteins following translation. Based on the computer analysis of HSP 70 cDNA, we postulate that similar to stress response proteins in melanogenesis, stress relief proteins in myocardial cells may also be modulated by the same ER resident protein, calnexin.
Department of Dermatology, University of Alberta, Edmonton, Canada.
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Vinayagamoorthy
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AR
Rajakumar
D002135:Calcium-Binding Proteins / Q000378:metabolism*; D037281:Calnexin; D003198:Computer Simulation; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D009206:Myocardium / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D006360:Heat-Shock Proteins; D037281:Calnexin