Rap signaling is crucial for the competence of IL-7 response and the development of B-lineage cells

Yoshinori Katayama, Miho Sekai, Masakazu Hattori, Ichiro Miyoshi, Yoko Hamazaki, Nagahiro Minato

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Rap family GTPases consist of multiple members with substantial functional redundancy. With the use of transgenic mice conditionally expressing a bona fide dominant-negative Rap1 mutant, Rap1A17, capable of inhibiting the activation of all Rap family members in B-lineage cells (mb.1-Rap1A17 Tg), we demonstrate that these mice show a defective generation of pre-B cells in bone marrow, resulting in a significant diminution of peripheral mainstream B cells. The effect is attributed to the impaired survival and expansion of B-lineage progenitors in response to IL-7, despite normal IL-7Rα expression. The pre-B cells from mb.1-Rap1A17 Tg mice showed a significantly reduced expression of c-myc and E2A, and the competence of IL-7 response was restored by the transduction of c-myc, but not by constitutively active (CA) Stat5a, CAPI3K-p100, or bcl-2. The residual follicular B cells with complete Cre-mediated recombination proliferated normally in response to B-cell receptor stimulation and showed efficient germinal center reaction in vivo. These results show that endogenous Rap signaling plays a crucial role selectively in B-lineage cell development by sustaining the competence for IL-7 response, whereas it is dispensable for mature B-cell function.

Original languageEnglish
Pages (from-to)1768-1775
Number of pages8
Issue number9
Publication statusPublished - 2009


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