Pepe V H, Sonenshein G E, Yoshimura M I, Shulman M J
J Immunol. 1986 Oct 1;137(7):2367-72.
Several lines of evidence suggest that immunoglobulin (Ig) light (L) chain plays a role in the secretion of heavy (H) chain. For example, myeloma variant lines, which synthesize the Ig H chain but not the L chain, fail to secrete H chain protein. Here we have tested directly the role of chain assembly in the control of Ig secretion by the transfer of functional L chain genes into two such L chain-defective myeloma mutants. A lambda 2 or kappa L chain gene was introduced into variant lines of the mouse myelomas MOPC 315 (IgA, lambda 2) or PC7 (IgM, kappa), respectively. Although the two mutant lines are unable to secrete the H chain they produce, rescue of secretion of complete Ig protein molecules (IgA or IgM) was observed after transfection. These results imply that the secretory apparatus of these cells is intact and that the failure to secrete free H chain reflects a structural feature intrinsic to that protein. The implications of these results with respect to control of secretion of multi-subunit proteins are discussed.
多项证据表明，免疫球蛋白（Ig）轻链（L链）在重链（H链）的分泌中发挥作用。例如，合成Ig H链但不合成L链的骨髓瘤变异株无法分泌H链蛋白。在此，我们通过将功能性L链基因导入两个此类L链缺陷型骨髓瘤突变体，直接测试了链组装在Ig分泌控制中的作用。分别将λ2或κL链基因导入小鼠骨髓瘤MOPC 315（IgA，λ2）或PC7（IgM，κ）的变异株。尽管这两个突变株无法分泌它们产生的H链，但转染后观察到完整Ig蛋白分子（IgA或IgM）的分泌得到了挽救。这些结果表明，这些细胞的分泌装置是完整的，未能分泌游离H链反映了该蛋白固有的结构特征。讨论了这些结果对多亚基蛋白分泌控制的意义。
