Binds to type I and II regulatory subunits of protein kinase A and anchors them to the cytoplasmic face of the mitochondrial outer membrane (By similarity). Involved in mitochondrial-mediated antiviral innate immunity (PubMed:31522117). Promotes translocation of NDUFS1 into mitochondria to regulate mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) activity (By similarity). Interacts with SLC8A3 (By similarity). Interacts with CFAP91 (PubMed:12223483). Interacts with CLPB (PubMed:31522117). Interacts with NDUFS1 (By similarity). Isoform 1 is detected in thymus, prostate, testis, ovary, colon and small intestine (PubMed:8769136). Isoform 2 is highly expressed in testis and detected at much lower levels in kidney, pancreas, liver, lung and brain (PubMed:7499250). RII-alpha binding site, predicted to form an amphipathic helix, could participate in protein-protein interactions with a complementary surface on the R-subunit dimer. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay.