Calcium signals regulate the functional differentiation of thymic iNKT cells

EMBO J. 2021 Aug 16;40(16):e107901. doi: 10.15252/embj.2021107901. Epub 2021 Jun 25.


How natural or innate-like lymphocytes generate the capacity to produce IL-4 and other cytokines characteristic of type 2 immunity remains unknown. Invariant natural killer T (iNKT) cells differentiate in the thymus into NKT1, NKT2, and NKT17 subsets, similar to mature, peripheral CD4+ T helper cells. The mechanism for this differentiation was not fully understood. Here, we show that NKT2 cells required higher and prolonged calcium (Ca2+ ) signals and continuing activity of the calcium release-activated calcium (CRAC) channel, than their NKT1 counterparts. The sustained Ca2+ entry via CRAC pathway in NKT2 cells was apparently mediated by ORAI and controlled in part by the large mitochondrial Ca2+ uptake. Unique properties of mitochondria in NKT2 cells, including high activity of oxidative phosphorylation, may regulate mitochondrial Ca2+ buffering in NKT2 cells. In addition, the low Ca2+ extrusion rate may also contribute to the higher Ca2+ level in NKT2 cells. Altogether, we identified ORAI-dependent Ca2+ signaling connected with mitochondria and cellular metabolism, as a central regulatory pathway for the differentiation of NKT2 cells.

Keywords: T-cell differentiation; calcium signaling; iNKT cells; metabolism; mitochondria.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calcium Release Activated Calcium Channels / metabolism
  • Calcium Signaling
  • Cell Differentiation*
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mitochondria / metabolism
  • Natural Killer T-Cells / metabolism*
  • Thymus Gland / cytology*


  • Calcium Release Activated Calcium Channels
  • Calcium

Associated data

  • GEO/GSE114555