LRRC8A-dependent volume regulated anion channel activity is dispensable for T cell development and function

Publication date: Available online 10 February 2017
Source:Journal of Allergy and Clinical Immunology
Author(s): Craig D. Platt, Janet Chou, Patrick Houlihan, Yousef R. Badran, Lalit Kumar, Wayne Bainter, P. Luigi Poliani, Carlos J. Perez, Sharon Y.R. Dent, David E. Clapham, Fernando Benavides, Raif S. Geha
BackgroundLeucine-rich repeat containing 8A (LRRC8A) is a ubiquitously expressed transmembrane protein with 17 LRRs at its C-terminal end, and is an essential component of the volume regulated anion channel (VRAC) which controls cellular volume. A heterozygous mutation in LRRC8A that truncates the two terminal LRRs was reported in a patient with agammaglobulinemia and absent B cells, and was demonstrated to exert a dominant negative effect on T and B cell development in mice. Lrrc8a^-/- mice have severely defective T cell development and function. It is not known whether the T and B cell defects caused by LRRC8A deficiency are caused by loss of VRAC activity.ObjectiveTo determine whether VRAC activity is required for normal T cell development and function.MethodsVRAC activity was examined by patch clamp analysis. Flow cytometry was used to examine T cell development. T cell proliferation, cytokine secretion and antibody titers were measured by standard techniques.ResultsWe demonstrate that the spontaneous mouse mutant ébouriffé (ebo/ebo) harbors a homozygous 2 bp frameshift mutation in Lrrc8a that truncates the fifteen terminal LRRs of LRRC8A. The LRRC8A^ebo mutation does not impact protein expression but drastically diminishes VRAC activity in T cells. ebo/ebo mice share features with Lrrc8a^-/- mice that include curly hair, infertility, reduced longevity and kidney abnormalities. However, in contrast to Lrrc8a^-/- mice, ebo/ebo mice have normal T cell development and function and intact antibody response to T-dependent antigen.ConclusionLRRC8A-dependent VRAC activity is dispensable for T cell development and function.

Teaser

The role that LRRC8A plays in T cell development is independent of its role in regulating cellular volume.


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