Association of ANA, a member of the antiproliferative tob family proteins, with a Caf1 component of the CCR4 transcriptional regulatory complex

A 35-kDa protein, ANA, belongs to an emerging family of antiproliferative proteins consisting of Tob, Tob2, ANA/BTG3, PC3B, PC3/TIS21/BTG2, and BTG1. All of these, except ANA and PC3B, have been shown to interact with the CCR4 transcription factor-associated protein Caf1. Here we show that ANA also associates with Caf1, ANA being the preferred partner of Caf1 among the Tob family proteins. Although ANA is likely to interact with Caf1 at its amino-terminal half, which is conserved among the family members, our data suggest that the carboxyl-terminal half of ANA plays a role in the interaction. Finally, in situ hybridization experiments revealed that expression of Caf1 overlaps at least in part with that of ANA. Thus, ANA could function through its interaction with Caf1.