Regulation of murine B lymphocyte plasma membrane protein turnover and shedding.

Lactoperoxidase-catalyzed cell surface radioiodination was employed to radiolabel murine splenic B-cell membrane immunoglobulins (IgM and IgD) and alloantigens encoded by the Major Histocompatibility Complex (I-Ak, I-Ek, H-2Kk, H-2Dk). The fate of the radiolabeled proteins was monitored by in vitro culture of labeled cells and isolation of labeled antigens from detergent lysates of the cells or culture fluids obtained at different times during culture. The effects of temperature, antimetabolites, colchicine, and cytochalasins on membrane protein catabolism demonstrated heterogeneity in rate, energy dependence, and cytoskeletal control of turnover suggesting that functional domains of turnover control exist in the B lymphocyte membrane.