This family consists of several eukaryotic TBP-1 interacting protein (TBPIP) sequences. TBP-1 has been demonstrated to interact with the human immunodeficiency virus type 1 (HIV-1) viral protein Tat, then modulate the essential replication process of HIV. In addition, TBP-1 has been shown to be a component of the 26S proteasome, a basic multiprotein complex that degrades ubiquitinated proteins in an ATP-dependent fashion. Human TBPIP interacts with human TBP-1 then modulates the inhibitory action of human TBP-1 on HIV-Tat-mediated transactivation [1]. TBPIP was found to be an activator that specifically stimulates the homologous pairing catalyzed by DMC1. Family members also include yeast homologous-pairing protein 2 (Hop2) and its homologues from animals and plants. They are required for proper homologous pairing and efficient cross-over and intragenic recombination during meiosis [2, 3, 4, 5].

1: Molecular cloning and characterization of a human homologue of TBPIP, a BRCA1 locus-related gene. Ijichi H, Tanaka T, Nakamura T, Yagi H, Hakuba A, Sato M; Gene 2000;248:99-107. PMID:10806355

2: The meiosis-specific Hop2 protein of S. cerevisiae ensures synapsis between homologous chromosomes. Leu JY, Chua PR, Roeder GS; Cell. 1998;94:375-386. PMID:9708739

3: A novel meiosis-specific protein of fission yeast, Meu13p, promotes homologous pairing independently of homologous recombination. Nabeshima K, Kakihara Y, Hiraoka Y, Nojima H; EMBO J. 2001;20:3871-3881. PMID:11447128

4: Positive role of the mammalian TBPIP/HOP2 protein in DMC1-mediated homologous pairing. Enomoto R, Kinebuchi T, Sato M, Yagi H, Shibata T, Kurumizaka H, Yokoyama S; J Biol Chem. 2004;279:35263-35272. PMID:15192114

5: Molecular cloning and characterization of a novel TBP-1 interacting protein (TBPIP):enhancement of TBP-1 action on Tat by TBPIP. Tanaka T, Nakamura T, Takagi H, Sato M; Biochem Biophys Res Commun. 1997;239:176-181. PMID:9345291