T cell cholesterol transport links intestinal immune responses to dietary lipid absorption

The intrinsic pathways that control membrane organization in immune cells and their impact on cellular functions are poorly defined. We found that the nonvesicular cholesterol transporter Aster-A linked plasma membrane (PM) cholesterol availability in CD4 T cells to systemic metabolism. Aster-A was recruited to the PM during T cell receptor (TCR) activation, where it facilitated the removal of accessible cholesterol. Loss of Aster-A increased cholesterol accumulation in the PM, which enhanced TCR nanoclustering and signaling. Aster-A associated with stromal interaction molecule 1 (STIM1) and negatively regulated calcium (Ca²⁺) flux. Aster-A deficiency promoted CD4 T cells to acquire a T helper 17 (T_H17) phenotype and stimulated interleukin-22 production, which reduced intestinal fat absorption and conferred resistance to diet-induced obesity. These findings delineate how immune cell membrane homeostasis links to systemic physiology.