Association of ANA, a Member of the Antiproliferative Tob Family Proteins, with a Cafl 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 Cafl. Here we show that ANA also associates with Cafl, ANA being the preferred partner of Cafl among the Tob family proteins. Although ANA is likely to interact with Cafl at its amino‐terminal hall', 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.