Structure and function of stress proteins

点击翻译按钮获取中文摘要

Experiment of antisense transfection was performed to elucidate the function of HSP47, a collagen-specific molecular chaperone. Stable transfectant expressing the antisense RNA of HSP47 were found to synthesize reduced amounts of type I collagen as well. When cDNA encoding alpha1 (I) collagen gene was transfected into these cell lines, overexpressed collagen was recovered in the detergent-insoluble fraction, suggesting the chaperone function of HSP47 which maintain the nascent polypeptide of collagen to be soluble in the endoplasmic reticulum.Molecular mechanism on the recognition of target proteins by GroEL was analyzed using alpha-lactalbumin (alpha-LA). Dissociation constants, effect of ioninc strength and rate constants of the interaction of GroEL with alpha-LA in the reduced state as well as in the moleten globule state were determined.Two independent pathways of the transports of nascent proteins into mitochondria were established : MSF-dependent pathway where nascent proteins are targeted to membrane receptors via the function of MSF,and MSF-independent pathway where proteins are directly handled to Mas20/Mass22 receptor on the mitochondrial membrane.A novel membrane protein, Rer1p, was found in the golgi membrane. Rer1p was suggested to be involved in the quality control mechanism since the incorrectly transported proteins to the Golgi are returned back to the endoplasimic reticulum by the function of this protein.