Regulates intracellular concentrations of taurine and glutamate. Negatively modulates SLC1A1/EAAC1 glutamate transport activity by decreasing its affinity for glutamate in a PKC activity-dependent manner. Plays a role in the retention of SLC1A1/EAAC1 in the endoplasmic reticulum. Homodimer. Heterodimer with ARL6IP1. Forms multimers. Interacts with ARL6. Interacts with prenylated RAB1A and RAB3A. Interacts with SLC1A1/EAAC1. Interacts with RTN2 (via first transmembrane domain). Does not interact with VAMP1, VAMP2 or VAMP3. Also exists as a soluble form in the cytoplasm. Associated with microtubules. By methyl-beta-cyclodextrin (By similarity). Up-regulated upon induced differentiation and in heat stress. Belongs to the PRA1 family.