title: The non-Ig parts of the VpreB and λ5 proteins of the surrogate light chain play opposite roles in the surface representation of the precursor B cell receptor.
abstract: The VpreB and λ5 proteins, together with Igμ-H chains, form precursor BCRs (preBCRs). We established λ5(-/-)/VpreB1(-/-)/VpreB2(-/-) Abelson virus-transformed cell lines and reconstituted these cells with λ5 and VpreB in wild-type form or with a deleted non-Ig part. Whenever preBCRs had the non-Ig part of λ5 deleted, surface deposition was increased, whereas deletion of VpreB non-Ig part decreased it. The levels of phosphorylation of Syk, SLP65, or PLC-γ2, and of Ca(2+) mobilization from intracellular stores, stimulated by μH chain crosslinking Ab were dependent on the levels of surface-bound preBCRs. It appears that VpreB probes the fitness of newly generated VH domains of IgH chains for later pairing with IgL chains, and its non-Ig part fixes the preBCRs on the surface. By contrast, the non-Ig part of λ5 crosslinks preBCRs for downregulation and stimulation.
authors.affiliation: Research Group of Lymphocyte Development, Max Planck Institute for Infection Biology, Berlin 10117, Germany. knoll@mpiib-berlin.mpg.de
authors.forename: Marko
authors.initials: M
authors.lastname: Knoll
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yanagisawa
authors.forename: Szandor
authors.initials: S
authors.lastname: Simmons
authors.forename: Niklas
authors.initials: N
authors.lastname: Engels
authors.forename: Jürgen
authors.initials: J
authors.lastname: Wienands
authors.forename: Fritz
authors.initials: F
authors.lastname: Melchers
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ohnishi
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D054444:Immunoglobulin Light Chains, Surrogate / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D010766:Phosphorylation; D054420:Pre-B Cell Receptors / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D054444:Immunoglobulin Light Chains, Surrogate; D054420:Pre-B Cell Receptors; C515636:immunoglobulin lambda-like polypeptide 1, mouse