SEQUENTIAL INTERACTION OF THE CHAPERONES BIP AND GRP94 WITH IMMUNOGLOBULIN-CHAINS IN THE ENDOPLASMIC-RETICULUM

被引:357
作者
MELNICK, J [1 ]
DUL, JL [1 ]
ARGON, Y [1 ]
机构
[1] DUKE UNIV,MED CTR,DEPT IMMUNOL,DURHAM,NC 27710
关键词
D O I
10.1038/370373a0
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
During their transit through the endoplasmic reticulum, newly synthesized light and heavy chains of immunoglobulins associate with two endoplasmic reticulum stress proteins. BiP/GRP78, a member of the HSP70 family, binds these polypeptides, presumably through promiscuously exposed hydrophobic sequences(1,2), soon after their translocation into the endoplasmic reticulum(3,4). GRP94, another endoplasmic reticulum stress protein(5,6) homologous to HSP90(7-11), also associates,vith unassembled immunoglobulin chains(12), but its interaction is biochemically, kinetically and structurally distinct from BiP's. We report here that whereas BiP preferentially binds an early disulphide intermediate of light chain and dissociates within a few minutes, GRP94 exclusively binds fully oxidized molecules and dissociates with a half-time of 50 min. These results indicate that GRP94 is itself a chaperone which acts after BiP.
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页码:373 / 375
页数:3
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