TY - JOUR
T1 - Different assembly species of IgM are directed to distinct degradation sites along the secretory pathway
AU - Rabinovich, E.
AU - Bar-Nun, S.
AU - Amitay, R.
AU - Shachar, I.
AU - Gur, B.
AU - Taya, M.
AU - Haimovich, J.
PY - 1993/11/15
Y1 - 1993/11/15
N2 - In 38C B lymphocytes the membrane form of IgM is displayed on the cell surface whereas the secretory form of IgM is degraded. In the EH cell line, a light chain-deficient variant of 38C cells, the μ heavy chains are partially assembled with surrogate light chains characteristic of pre-B cells. In these cells neither the membrane (μm) nor the secretory (μs) forms of the μ heavy chain reach their final destination, and both are rapidly degraded. The degradation of μ chains in EH cells, like that of μs in 38C cells, is nonlysosomal and occurs prior to the frone-Golgi. However, while μs degradation in 38C cells is inhibited by brefeldin A, in EH cells μs and μm are retained and degraded by a brefeldin A-insensitive mechanism. These results indicate that degradation in EH cells occurs within the endoplasmic reticulum, whereas degradation in 38C cells requires exit from this compartment. Thus, μ heavy chains can be degraded in multiple sites along the secretory pathway. The location of the degradation process is determined by the developmentally regulated assembly species of the μ chains with either "classical" or surrogate light chains.
AB - In 38C B lymphocytes the membrane form of IgM is displayed on the cell surface whereas the secretory form of IgM is degraded. In the EH cell line, a light chain-deficient variant of 38C cells, the μ heavy chains are partially assembled with surrogate light chains characteristic of pre-B cells. In these cells neither the membrane (μm) nor the secretory (μs) forms of the μ heavy chain reach their final destination, and both are rapidly degraded. The degradation of μ chains in EH cells, like that of μs in 38C cells, is nonlysosomal and occurs prior to the frone-Golgi. However, while μs degradation in 38C cells is inhibited by brefeldin A, in EH cells μs and μm are retained and degraded by a brefeldin A-insensitive mechanism. These results indicate that degradation in EH cells occurs within the endoplasmic reticulum, whereas degradation in 38C cells requires exit from this compartment. Thus, μ heavy chains can be degraded in multiple sites along the secretory pathway. The location of the degradation process is determined by the developmentally regulated assembly species of the μ chains with either "classical" or surrogate light chains.
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AN - SCOPUS:0027484157
SN - 0021-9258
VL - 268
SP - 24145
EP - 24148
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 32
ER -