Phosducin-like proteins (PhLP) are small, thioredoxin domain-containing proteins that are highly conserved across unicellular and multicellular organisms. The PhLP family is organized into three subgroups based primarily on sequence similarities and proposed cellular functions. The PhLP1 group is involved in the folding, stabilizing, and regulating the beta-gamma dimers of trimeric G-proteins. Members of the PhLP2 and PhLP3 groups are hypothesized to function as co-chaperones in conjunction with the Chaperonin-containing TCP-1 complex. (Adapted from FBrf0260832.)