Crosslinking of the surface immunoglobulin receptor in B lymphocytes induces a redistribution of neurofibromin but not p120-GAP

Boyer, M. J., Gutmann, D. H., Collins, F. S., Bar-Sagi, D. (February 1994) Crosslinking of the surface immunoglobulin receptor in B lymphocytes induces a redistribution of neurofibromin but not p120-GAP. Oncogene, 9 (2). pp. 349-57. ISSN 0950-9232 (Print)

URL: http://www.ncbi.nlm.nih.gov/pubmed/8290249

Abstract

The activation of Ras proteins is a key step in the signal transduction pathways triggered by ligand-bound cell surface receptors. The GTPase activating proteins (GAPs) p120-GAP and neurofibromin, the neurofibromatosis-type 1 (NF1) gene product, are thought to play an essential role in the regulation of Ras activity by increasing the GTPase activity of wild type, but not activated Ras in vitro. Both GAPs are widely expressed in mammalian tissues thus raising the question of whether or not they have different regulatory functions. In this study, we have analysed the distribution of p120-GAP and neurofibromin in splenic B lymphocytes by immunofluorescent staining. Crosslinking of surface immunoglobulin (slg), the B-lymphocyte antigen receptor, induced the redistribution of neurofibromin. In contrast, no apparent change in the cellular localization of p120-GAP occurred followed the cross-linking of slg. The redistribution of neurofibromin coincided both spatially and temporally with the relocalization of crosslinked slg and was inhibited by the cytoskeletal disrupting agents colchicine and cytochalasin D. These findings indicated that neurofibromin and p120-GAP can be differentially regulated in vivo and suggest that neurofibromin is a component of the signaling pathway initiated by crosslinking of B lymphocyte slg. Furthermore, our observations that cocapping neurofibromin with slg is independent of the p21ras redistribution suggests that the role of neurofibromin in B cells is not solely related to its ability to act as a Ras regulator.

Item Type: Paper
Uncontrolled Keywords: Animals B-Lymphocytes/ chemistry/physiology/ultrastructure Cells, Cultured Colchicine/pharmacology Cross-Linking Reagents Cytochalasin D/pharmacology Fluorescent Antibody Technique GTPase-Activating Proteins Lovastatin/pharmacology Mice Mice, Inbred BALB C Neurofibromin 1 Oncogene Protein p21(ras)/analysis/physiology Phosphorylation Proteins/ analysis/ metabolism/physiology Receptor Aggregation/physiology Receptors, Antigen, B-Cell/ analysis/ metabolism Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. Signal Transduction/physiology Spleen/cytology ras GTPase-Activating Proteins
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > GTPase
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > G protein > Ras
organs, tissues, organelles, cell types and functions > tissues types and functions > signal transduction
CSHL Authors:
Communities: CSHL labs
Depositing User: Matt Covey
Date: February 1994
Date Deposited: 04 May 2015 15:24
Last Modified: 04 May 2015 15:24
URI: http://repository.cshl.edu/id/eprint/31479

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