Interacts with RIMS1 and RIMS2 (By similarity). Interacts with TSPO. Preferentially expressed in the mitochondria in the presence of TSPO. Predominantly expressed in brain, pituitary gland and thymus in adults. In adult brain, highest expression found in temporal lobe and the putamen, followed by amygdala, caudate nucleus, cerebral cortex, occipital and frontal lobe. A high expression level is also observed in fetal tissues like brain, heart, kidney and thymus. The SH3 and proline-rich domain is required for the interaction with TSPO and the second SH3 domain mediates binding to a proline-rich motif in RIMS1 and RIMS2. Belongs to the RIMBP family. PubMed:9915832 demonstrated interaction with TSPO but later PubMed:12435798 demonstrated in the rat ortholog that is not associated with TSPO in the brain.