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Author Notes:

Address correspondence to Max D. Cooper.

We are grateful to our colleagues, Drs. Hiromi Kubagawa and Peter Burrows, for providing reagents, helpful discussions, and encouragement. We thank Dr. Jun Minowada for the Nalm16 cell line, Dr. Prasad Srivastava for the anti-GRP antibodies, Dr. Michael Brenner for the IP-90 antibody and very helpful discussion, and Ann Brookshire for help in preparing the manuscript.

Subjects:

Research Funding:

These studies have been supported in part by National Institutes of Health grants AI30879 and CA13148 and by L'Association pour la Recherche Contre le Cancer. M. D. Cooper is a Howard Hughes Medical Institute Investigator. H. Illges is a recipient of a fellowship from the Deutsche Forschungsgemeinschaft.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Immunology
  • Research & Experimental Medicine
  • LYMPHOCYTES-PRE-B
  • MU HEAVY-CHAIN
  • SIGNAL-TRANSDUCTION
  • ANTIGEN RECEPTOR
  • BONE-MARROW
  • LAMBDA-LIKE
  • T-CELL
  • PROTEIN
  • COMPLEX
  • SURFACE

Fate of surrogate light chains in B lineage cells

Tools:

Journal Title:

Journal of Experimental Medicine

Volume:

Volume 183, Number 2

Publisher:

, Pages 421-429

Type of Work:

Article | Final Publisher PDF

Abstract:

Biosynthesis of the immunoglobulin (Ig) receptor components and their assembly were examined in cell lines representative of early stages in human B lineage development. In pro-B cells, the nascent surrogate light chain proteins form a complex that transiently associates in the endoplasmic reticulum with a spectrum of unidentified proteins (40, 60, and 98 kD) and Bip, a heat shock protein family member. Lacking companion heavy chains, the surrogate light chains in pro-B cells do not associate with either the Igα or Igβ signal transduction units, undergo rapid degradation, and fail to reach the pro-B cell surface. In pre-B cells, by contrast, a significant portion of the surrogate light chain proteins associate with μ heavy chains, Igα, and Igβ to form a stable receptor complex with a relatively long half-life. Early in this assembly process, Bip/GRP78, calnexin, GRP94, and a protein of ~17 kD differentially bind to the nascent μ heavy chains. The 17-kD intermediate is gradually replaced by the surrogate light chain protein complex, and the Igα and Igβ chains bind progressively to the μ heavy chains during the complex and relatively inefficient process of pre-B receptor assembly. The results suggest that, in humans, heavy chain association is essential for surrogate light chain survival and transport to the cell surface as an integral receptor component.

Copyright information:

© Rockefeller University Press.

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