title: A specific protein substrate for a deubiquitinating enzyme: Liquid facets is the substrate of Fat facets.
abstract: Eukaryotic genomes encode large families of deubiquitinating enzymes (DUBs). Genetic data suggest that Fat facets (Faf), a Drosophila DUB essential for patterning the compound eye, might have a novel regulatory function; Faf might reverse the ubiquitination of a specific substrate, thereby preventing proteasomal degradation of that protein. Additional genetic data implicate Liquid facets (Lqf), a homolog of the vertebrate endocytic protein epsin, as a candidate for the key substrate of Faf. Here, biochemical experiments critical to testing this model were performed. The results show definitively that Lqf is the key substrate of Faf in the eye; Lqf concentration is Faf-dependent, Lqf is ubiquitinated in vivo and deubiquitinated by Faf, and Lqf and Faf interact physically.
authors.affiliation: Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.forename: Janice A
authors.initials: JA
authors.lastname: Fischer
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000201:enzymology* / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000201:enzymology; D010450:Endopeptidases / Q000172:deficiency / Q000378:metabolism*; D005123:Eye / Q000166:cytology / Q000196:embryology* / Q000201:enzymology; D005260:Female; D006168:Guinea Pigs; D009479:Neuropeptides / Q000378:metabolism*; D011233:Precipitin Tests; D013379:Substrate Specificity; D014452:Ubiquitins / Q000378:metabolism*; D033921:Vesicular Transport Proteins
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D009479:Neuropeptides; D014452:Ubiquitins; D033921:Vesicular Transport Proteins; C114154:epsin; D010450:Endopeptidases; C059237:ubiquitin-Nalpha-protein hydrolase