Acts as a positive regulator of T-cell maturation and inflammatory function. Required for several functions of T-cells, in both the CD4(+) and the CD8(+) compartments and this includes expression of cell surface markers of activation, proliferation, and cytokine production in response to specific or non-specific stimulation (By similarity). Enhances NK cell cytotoxicity by positively regulating polarization of microtubule-organizing center (MTOC) to cytotoxic synapse, lytic granule transport along microtubules, and dynein-mediated clustering to MTOC (PubMed:25762780). Interacts with HSPA5 and stabilizes the interaction between HSPA5 and ERN1, leading to suppression of ERN1-induced JNK activation and endoplasmic reticulum stress-induced apoptosis (PubMed:21289099). Homodimer (PubMed:25762780). Interacts with DOCK8 (PubMed:25762780). Interacts (via C-terminus) with intact microtubules (PubMed:25762780). Interacts with dynein-dynactin motor complex (PubMed:25762780). Interacts (via C-terminus) with HSPA5 (PubMed:21289099). Expressed in endothelium (at protein level) (PubMed:21289099). Expressed in NK cells (at protein level) (PubMed:25762780). By endoplasmic reticulum stress. Belongs to the CCDC88 family.