Melnick J, Aviel S, Argon Y
Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710.
J Biol Chem. 1992 Oct 25;267(30):21303-6.
The molecular chaperone BiP/GRP78 associates with various polypeptides in the endoplasmic reticulum, including immunoglobulin chains. We now show, using chemical cross-linking, that another endoplasmic reticulum stress protein, GRP94, associates with newly synthesized immunoglobulin light and heavy chains. We demonstrate the presence of ternary complexes composed of immunoglobulin chains, BiP and GRP94. Because both BiP and GRP94 associate far less with fully assembled immunoglobulin than with unassembled subunits, our data suggest that GRP94, like BiP, functions as a molecular chaperone. The presence of both BiP and GRP94 in the same complex further suggests that the two stress proteins work in concert during the folding and assembly of immunoglobulins.
分子伴侣BiP/GRP78在内质网中与多种多肽结合，包括免疫球蛋白链。我们现在通过化学交联表明，另一种内质网应激蛋白GRP94与新合成的免疫球蛋白轻链和重链结合。我们证明了由免疫球蛋白链、BiP和GRP94组成的三元复合物的存在。由于BiP和GRP94与完全组装的免疫球蛋白的结合远少于与未组装亚基的结合，我们的数据表明GRP94与BiP一样，起着分子伴侣的作用。同一复合物中同时存在BiP和GRP94，进一步表明这两种应激蛋白在免疫球蛋白的折叠和组装过程中协同发挥作用。
