Mitochondrial Carrier Homolog 1 (MTCH1)

The deduced 371-amino acid PSAP protein has a predicted molecular mass of 39.9 kD and contains a PDZ-like domain and several putative protein kinase C and tyrosine kinase phosphorylation sites. Northern blot analysis of multiple human tissues detected a 1.9-kb PSAP transcript with highest expression in brain, lower expression in heart, and barely detectable expression in all other tissues tested. PSAP shares 28% sequence identity and 65% similarity with the C. elegans protein F43E2.7. PSAP and full-length PSEN1 coimmunoprecipitate in HEK293 cells, indicating that the proteins interact in vivo. Using deletion mutants, they determined that the 4-amino acid consensus sequence (gln-phe-tyr-ile) for binding PDZ domains at the extreme C terminus of PSEN1 is required for binding PSAP.