TY - JOUR
T1 - Immunoglobulin light chains dictate vesicular transport-dependent and -independent routes for IgM degradation by the ubiquitin-proteasome pathway
AU - Elkabetz, Yechiel
AU - Kerem, Anat
AU - Tencer, Lilach
AU - Winitz, Dorit
AU - Kopito, Ron R.
AU - Bar-Nun, Shoshana
PY - 2003/5/23
Y1 - 2003/5/23
N2 - Degradation of IgM μ heavy chains in light chain-negative pre-B cells is independent of vesicular transport, as is evident by its insensitivity to brefeldin A or cell permeabilization. Conversely, by the same criteria, degradation of the secretory μs heavy chain in light chain-expressing B cells depends on vesicular transport. To investigate whether the presence of conventional light chains or the developmental stage of the B-lymphocytes dictates the degradative route taken by μ, we express in 70Z/3 pre-B cells either λ ectopically or κ by lipopolysaccharides-stimulated differentiation into B cells and show their assembly with μ heavy chains. The resulting sensitivity of μ degradation to brefeldin A and cell permeabilization demonstrates that conventional light chains, a hallmark of B cell differentiation, are necessary and sufficient to divert μ from a vesicular transport-independent to a vesicular transport-dependent degradative route. Although both routes converge at the ubiquitin-proteasome degradation pathway, only in light chain-expressing cells is vesicular transport a prerequisite for μ ubiquitination.
AB - Degradation of IgM μ heavy chains in light chain-negative pre-B cells is independent of vesicular transport, as is evident by its insensitivity to brefeldin A or cell permeabilization. Conversely, by the same criteria, degradation of the secretory μs heavy chain in light chain-expressing B cells depends on vesicular transport. To investigate whether the presence of conventional light chains or the developmental stage of the B-lymphocytes dictates the degradative route taken by μ, we express in 70Z/3 pre-B cells either λ ectopically or κ by lipopolysaccharides-stimulated differentiation into B cells and show their assembly with μ heavy chains. The resulting sensitivity of μ degradation to brefeldin A and cell permeabilization demonstrates that conventional light chains, a hallmark of B cell differentiation, are necessary and sufficient to divert μ from a vesicular transport-independent to a vesicular transport-dependent degradative route. Although both routes converge at the ubiquitin-proteasome degradation pathway, only in light chain-expressing cells is vesicular transport a prerequisite for μ ubiquitination.
UR - http://www.scopus.com/inward/record.url?scp=0038143181&partnerID=8YFLogxK
U2 - 10.1074/jbc.M208730200
DO - 10.1074/jbc.M208730200
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AN - SCOPUS:0038143181
SN - 0021-9258
VL - 278
SP - 18922
EP - 18929
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 21
ER -