This family represents the protein product of the gene pha-1 which coordinates with lin-35 Rb during animal development. The protein is expressed during embryonic development and functions in the cytoplasm. PHA-1 acts in a parallel pathway with UBC-18 to regulate the activity of a common cellular target [1].

1: The coordinate regulation of pharyngeal development in C. elegans by lin-35/Rb, pha-1, and ubc-18. Fay DS, Qiu X, Large E, Smith CP, Mango S, Johanson BL; Dev Biol. 2004;271:11-25. PMID:15196946