Protein and peptide binding and stimulation of in vitro lysosomal proteolysis by the 73-kDa heat shock cognate protein.
Protein and peptide binding and stimulation of in vitro lysosomal proteolysis by the 73-kDa heat shock cognate protein.
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DOI：
10.1016/s0021-9258(19)50408-2
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发表时间：
1992-05
期刊：
影响因子：
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通讯作者：
S. R. Terlecky;H. Chiang;T. Olson;J. Dice
中科院分区：
文献类型：
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作者：
S. R. Terlecky;H. Chiang;T. Olson;J. Dice
在血清戒断期间细胞内蛋白质的溶酶体降解由70-kDa热休克蛋白（hsp 70）家族的成员刺激（Chiang，H. L.，Terlecky，S. R.，普兰特，C. P.，和Dice，J.F.（1989）Science 246，382-385）。通过RNase S-肽-Sepharose亲和层析分离的这种hsp 70被称为73-kDa肽识别蛋白（prp 73）。我们现在报道prp 73与几种蛋白质和肽结合，这些蛋白质和肽的降解率在血清戒断过程中增加。prp 73也与五肽KFERQ结合，并且更弱地与KFERQ序列内具有单个氨基酸取代的大多数修饰的RNase S-肽衍生物结合。综上所述，这些结果表明，prp 73在与KFERQ生物化学相关的肽区结合多种蛋白质。三条证据表明prp 73是73 kDa的热休克同源蛋白（hsc 73）：（a）在所测试的五种hsp 70中，hsc 73与RNA酶S-肽结合最强烈，（B）prp 73和hsc 73两者也与RNA酶A和天冬氨酸氨基转移酶结合，但不与卵清蛋白、溶菌酶或泛素结合，和（c）prp 73和hsc 73在体外均促进溶酶体对[3 H] RNase S-肽的摄取和降解，而在该测定中其它三种hsp 70没有活性。
Lysosomal degradation of intracellular proteins during serum withdrawal is stimulated by a member of the 70-kDa heat shock protein (hsp70) family (Chiang, H.-L., Terlecky, S. R., Plant, C. P., and Dice, J. F. (1989) Science 246, 382-385). This hsp70, isolated by affinity chromatography with RNase S-peptide-Sepharose, is referred to as the 73-kDa peptide recognition protein (prp73). We now report that prp73 binds to several proteins and peptides whose degradative rates are increased during serum withdrawal. prp73 also binds to the pentapeptide, KFERQ, and more weakly to most modified RNase S-peptide derivatives with a single amino acid substitution within the KFERQ sequence. Taken together, these results suggest that prp73 binds to a variety of proteins at peptide regions biochemically related to KFERQ. Three lines of evidence indicate that prp73 is the heat shock cognate protein of 73 kDa (hsc73): (a) among five hsp70s tested, hsc73 binds to RNase S-peptide most avidly, (b) both prp73 and hsc73 also bind to RNase A and aspartate aminotransferase but not to ovalbumin, lysozyme, or ubiquitin, and (c) both prp73 and hsc73 promote uptake and degradation of [3H] RNase S-peptide by lysosomes in vitro, while three other hsp70s are without activity in this assay.