Volume 11 Issue 3, March 2010

Jeffrey Ravetch describes how he came to identify the in vivo function of the once mysterious Fc receptors.

Members of the transient receptor potential vanilloid ion-channel family are expressed in a wide variety of cells and function as sensors of mechanical stress. The second such family member, TVRP2, is now also linked to phagocytosis in macrophages.

A new study demonstrates that commitment to the CD8 lineage in the thymus requires sequential T cell antigen receptor (TCR) and interleukin 7 (IL-7) signaling. The TCR signal first induces IL-7 responsiveness, then recognition of IL-7 induces the nuclear factor Runx3, which specifies the CD8 lineage.

Transient formation of reactive oxygen species (ROS) accompanies B cell signaling and activation. Now the voltage-gated proton channel HVCN1 has been linked to ROS formation and B cell activation.

Hematopoietic stem cell self-renewal is tightly regulated. Regulation of the stability of c-Myc protein contributes to this control of hematopoietic stem cell quiescence and repopulation.

Hematopoietic stem cells infrequently proliferate, but their self-renewal is essential. Aifantis and colleagues show regulation of c-Myc protein stability by the ubiquitin ligase Fbw7 controls the self-renewal and differentiation potential of these cells.

Efficient antiviral responses require cross-priming of cytolytic T lymphocytes by dendritic cells. Randall and colleagues show that CD103⁻CD11b^hi dendritic cells directly cross-prime CD8⁺ T cells after influenza infection.

The identity of self antigens targeted in various autoimmune diseases is often unknown. Haskins and colleagues identify a chromagranin A epitope whose presentation by I-A^g7 involves an unusual peptide-binding mode.

Phagocytosis involves ionic flux, but the identity of the ion channels involved remains ill defined. Caterina and co-workers show that the cation channel TRPV2 is involved in particle binding and phagocytosis in macrophages.

Lymphocyte development requires transcription factors of the E2A family. Goldrath and colleagues identify a unique role for the E2 protein HEB in the generation and survival of invariant natural killer T cells.

How IL-9 expression is regulated remains unclear. Dong and co-workers show that the IL-25–IL-17RB pathway is central to the physiological regulation of this cytokine in vivo.

Whether CD8-lineage specification and CD8⁺ T cell differentiation is dependent on intrathymic cytokines signaling is unclear. Singer and co-workers show that interleukin 7 specifies CD8-lineage choice and promotes the differentiation of cytotoxic-lineage T cells.

Reactive oxygen species can enhance B cell antigen receptor (BCR) signaling strength. Dyer and colleagues show that the voltage-gated proton channel HVCN1 associates with BCRs and contributes to BCR signaling via the generation of reactive oxygen species.