PSMC3 Interacting Protein (PSMC3IP)

TBPIP interacted directly with TBP1 and enhanced TBP1-mediated inhibition of HIV Tat-mediated transactivation.The deduced protein contains 203 amino acids. Northern blot analysis detected a 1.6-kb transcript in all adult and fetal tissues examined, with abundant expression in testis, colon, a breast cancer cell line, and a lymphoma.The deduced 217-amino acid protein has several putative phosphorylation sites. RT-PCR detected Tbpip expression in CD4 positive T cells and in macrophages. In situ hybridization found Tbpip mRNA colocalized with Tbp1 in seminiferous tubules of adult mouse testis. Western blot analysis detected Tbpip at an apparent molecular mass of 24 kD. Immunohistochemical analysis of mouse testis detected Tbpip in nuclei of primary and secondary spermatocytes.