Vav1/2/3-null Mice Define an Essential Role for Vav Family Proteins in Lymphocyte Development and Activation but a Differential Requirement in MAPK Signaling in T and B Cells

Keiko Fujikawa, Ana V. Miletic, Frederick W. Alt, Roberta Faccio, Tracie Brown, Jeremy Hoog, Jessica Fredericks, Shinzo Nishi, Shirly Mildiner, Sheri L. Moores, Joan Brugge, Fred S. Rosen, Wojciech Swat

Research output: Contribution to journalArticlepeer-review

195 Scopus citations

Abstract

The Vav family of Rho guanine nucleotide exchange factors is thought to orchestrate signaling events downstream of lymphocyte antigen receptors. Elucidation of Vav function has been obscured thus far by the expression of three highly related family members. We generated mice lacking all Vav family proteins and show that Vav-null mice produce no functional T or B cells and completely fail to mount both T-dependent and T-independent humoral responses. Whereas T cell development is blocked at an early stage in the thymus, immature B lineage cells accumulate in the periphery but arrest at a late "transitional" stage. Mechanistically, we show that the Vav family is crucial for both TCR and B cell receptor (BCR)-induced Ca2+ signaling and, surprisingly, is only required for mitogen-activated protein kinase (MAPK) activation in developing and mature T cells but not in B cells. Thus, the abundance of immature B cells generated in Vav-null mice may be due to intact Ras/MAPK signaling in this lineage. Although the expression of Vav1 alone is sufficient for normal lymphocyte development, our data also reveal lineage-specific roles for Vav2 and Vav3, with the first demonstration that Vav3 plays a critical compensatory function in T cells. Together, we define an essential role for the entire Vav protein family in lymphocyte development and activation and establish the limits of functional redundancy both within this family and between Vav and other Rho-guanine nucleotide exchange factors.

Original languageEnglish
Pages (from-to)1595-1608
Number of pages14
JournalJournal of Experimental Medicine
Volume198
Issue number10
DOIs
StatePublished - Nov 17 2003

Keywords

  • Antigen receptor
  • Ca
  • Mitogen-activated protein kinase
  • Signal transduction
  • Thymocyte

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