The function of the Drosophila fat facets deubiquitinating enzyme in limiting photoreceptor cell number is intimately associated with endocytosis.
Fat facets is a deubiquitinating enzyme required in a cell communication pathway that limits to eight the number of photoreceptor cells in each facet of the Drososphila compound eye. Genetic data support a model whereby Faf removes ubiquitin, a polypeptide tag for protein degradation, from a specific ubiquitinated protein thus preventing its degradation. Here, mutations in the liquid facets gene were identified as dominant enhancers of the fat facets mutant eye phenotype. The liquid facets locus encodes epsin, a vertebrate protein associated with the clathrin endocytosis complex. The results of genetic experiments reveal that fat facets and liquid facets facilitate endocytosis and function in common cells to generate an inhibitory signal that prevents ectopic photoreceptor determination. Moreover, it is demonstrated that the fat facets mutant phenotype is extraordinarily sensitive to the level of liquid facets expression. We propose that Liquid facets is a candidate for the critical substrate of Fat facets in the eye.
Cadavid
A L
AL
Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712 USA.
Ginzel
A
A
Fischer
J A
JA
D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002452:Cell Count; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004330:Drosophila / Q000235:genetics / Q000502:physiology; D004705:Endocytosis / Q000502:physiology*; D010450:Endopeptidases / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010641:Phenotype; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology*; D033921:Vesicular Transport Proteins
D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D018076:DNA, Complementary; D009479:Neuropeptides; D033921:Vesicular Transport Proteins; C114154:epsin; D010450:Endopeptidases; C059237:ubiquitin-Nalpha-protein hydrolase