This family contains the C terminus of Saccharomyces cerevisiae Bul1. Bul1 binds the ubiquitin ligase Rsp5, via an N terminal PPSY motif (157-160 in Swiss:P48524) [1]. The complex containing Bul1 and Rsp5 is involved in intracellular trafficking of the general amino acid permease Gap1 [2], degradation of Rog1 in cooperation with Bul2 and GSK-3 [3], and mitochondrial inheritance [4]. Bul1 may contain HEAT repeats.

1: The PY-motif of Bul1 protein is essential for growth of Saccharomyces cerevisiae under various stress conditions. Yashiroda H, Kaida D, Toh-e A, Kikuchi Y; Gene 1998;225:39-46. PMID:9931424

2: Ubiquitin is required for sorting to the vacuole of the yeast general amino acid permease, Gap1. Soetens O, De Craene JO, Andre B; J Biol Chem 2001;276:43949-43957. PMID:11500494

3: Yeast glycogen synthase kinase 3 is involved in protein degradation in cooperation with Bul1, Bul2, and Rsp5. Andoh T, Hirata Y, Kikuchi A; Mol Cell Biol 2000;20:6712-6720. PMID:10958669

4: A role for ubiquitination in mitochondrial inheritance in Saccharomyces cerevisiae. Fisk HA, Yaffe MP; J Cell Biol 1999;145:1199-1208. PMID:10366593