CRACR2A (calcium release activated channel regulator 2A) is a multifunctional protein that serves as both a Rab GTPase and a calcium signaling regulator with critical roles in immune cell function and vascular biology. As a large Rab GTPase containing multiple functional domains, CRACR2A mediates vesicle trafficking, including the transport of Weibel-Palade bodies to microtubule organizing centers in endothelial cells during inflammatory responses 1. In T cells, CRACR2A acts as a crucial signaling module that bridges TCR-mediated calcium-NFAT and JNK pathways by translocating from the trans-Golgi network to the immunological synapse upon TCR stimulation 1 2. The protein enhances store-operated calcium entry (SOCE) by promoting STIM1-Orai1 interactions and undergoes calcium-dependent inactivation 3 4. CRACR2A promotes Th1 cell differentiation and Th17 effector functions, with deficiency leading to reduced autoimmune responses in experimental models 2. In neutrophils, CRACR2A facilitates calcium mobilization and β2 integrin activation, promoting neutrophil recruitment during sterile inflammation and ischemic stroke through STIM1 interactions 5. The protein's dysfunction has been linked to immunodeficiency and cancer progression, making it a potential therapeutic target 5 6.