Lymphoproliferative defects in mice lacking the expression of neurofibromin: Functional and biochemical consequences of Nf1 deficiency in T-cell development and function

David A. Ingram, Lei Zhang, Jennifer McCarthy, Mary Jo Wenning, Lucy Fisher, Feng Chun Yang, D. Wade Clapp, Reuben Kapur

Research output: Contribution to journalArticle

32 Scopus citations


Ras plays an essential role in lymphocyte development and function. However, in vivo consequence(s) of regulation of Ras activity by guanosine triphosphatase (GTPase)-activating proteins (GAPs) on lymphocyte development and function are not known. In this study we demonstrate that neurofibromin, the protein encoded by the NF1 tumor suppressor gene functions as a GAP for Ras in T cells. Loss of Nf1 in T cells results in enhanced Ras activation, which is associated with thymic and splenic hyperplasia, and an increase in the absolute number of immature and mature T-cell subsets compared with control mice. Interestingly, in spite of a profound T-cell expansion and higher thymidine incorporation in unstimulated Nf1-deficient T cells, T-cell receptor and interleukin-2 receptor-mediated proliferation of thymocytes and mature T cells was substantially reduced compared with control mice. Collectively, these results identify neurofibromin as a GAP for Ras in T cells for maintaining immune homeostasis in vivo.

Original languageEnglish (US)
Pages (from-to)3656-3662
Number of pages7
Issue number10
StatePublished - Nov 15 2002


ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

Cite this