Figure 8.

Assembly and Endo H sensitivity of BCR complexes. (A) Endo H sensitivity of μ chains. BJAB/babe (BJAB) and BJAB/K1 cells were metabolically labeled with [³⁵S]methionine and [³⁵S]cysteine for 30 min and chased for 1 and 4 h. Cells were lysed with 1% digitonin lysis buffer, and radioactively labeled lysates were used for immunoprecipitation with an anti-μ. μ chain immunoprecipitates were untreated (−) or treated (+) with Endo H before SDS-PAGE. Only the part of the gel displaying the μ chains is shown. The asterisk indicates the Endo H–sensitive forms of μ chains. (B) Assembly of BCR and Endo H sensitivity of Igα and Igβ. BJAB and BJAB/K1 cells were metabolically labeled with [³⁵S]methionine and [³⁵S]cysteine for 30 min and chased for 1 and 3 h. Cells were lysed with 1% digitonin lysis buffer, and radioactively labeled lysates were used for immunoprecipitation with an anti-Igα or anti-Igβ antibody. Anti-Igα or anti-Igβ immunoprecipitates were untreated (−) or treated (+) with Endo H before SDS-PAGE. Asterisks indicate the Endo H–sensitive forms of μ, Igα, and Igβ. The data were reproduced in three independent experiments.