Cells continuously take up nutrients and signaling molecules. Internalized proteins destined for degradation are routed from the plasma membrane through early endosomes, multivesicular bodies (MVBs), late endosomes and finally to lysosomes. The molecular mechanisms regulating these steps in endocytic trafficking are important, because they are altered by many genetic diseases including Chediak-Fligashi or Hermansky-Pudlak syndromes. The Drosophila compound eye is an excellent model system for a genetic analysis of endocytic trafficking. Mutations in many genes necessary for this process can be identified as eye color mutations because they also interfere with the delivery of biosynthetic cargo to pigment granules. Internalization of the Boss ligand into R7 photoreceptor cells provides a direct assay to follow endocytic trafficking. This proposal is aimed at exploiting these features of the Drosophila eye for a genetic dissection of endocytic trafficking in multicellular organisms. The (dor) deep orange and (car) carnation eye color genes encode two subunits of a complex that is necessary late in lysosomal delivery and eye pigmentation.
In Specific Aim 1, the rote of additional subunits of this complex in lysosomal delivery will be characterized.
In Specific Aim 2, the specific defects in endocytic and biosynthetic trafficking in dor mutant cells will be determined on the ultrastructural level by labeling different compartments with HRP fusion proteins. To exploit the exciting connection between lysosomal delivery and eye color mutations, Specific Aim 3 proposes a systematic screen for mutants affecting eye color and endocytic trafficking. Besides additional dor-like mutations acting late in the pathway, this screen will also yield mutations interfering with earlier steps in endocytic trafficking, for example, the regulation of MVB biogenesis and function.
Specific Aim 4 proposes the characterization of DmVps28 as an example for such mutations acting early in the endocytic pathway. An important long-term goal of this work is to relate defects in different trafficking mutations to the symptoms in genetic diseases altering endocytic trafficking. To directly compare phenotypes in the Drosophila model system, Specific Aim 5 is directed towards the isolation of mutations in the Drosophila Hermansky-Pudlak syndrome-1 gene and the characterization of the resulting defects in endocytic trafficking.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY010199-08
Application #
6333641
Study Section
Visual Sciences C Study Section (VISC)
Program Officer
Hunter, Chyren
Project Start
1994-04-01
Project End
2005-03-31
Budget Start
2001-04-01
Budget End
2002-03-31
Support Year
8
Fiscal Year
2001
Total Cost
$351,000
Indirect Cost
Name
University of Texas Sw Medical Center Dallas
Department
Neurosciences
Type
Schools of Medicine
DUNS #
City
Dallas
State
TX
Country
United States
Zip Code
75390
Sun, Qifei; Wu, Yipin; Jonusaite, Sima et al. (2018) Intracellular Chloride and Scaffold Protein Mo25 Cooperatively Regulate Transepithelial Ion Transport through WNK Signaling in the Malpighian Tubule. J Am Soc Nephrol 29:1449-1461
Moehlman, Andrew T; Casey, Amanda K; Servage, Kelly et al. (2018) Adaptation to constant light requires Fic-mediated AMPylation of BiP to protect against reversible photoreceptor degeneration. Elife 7:
Nandi, Nilay; Tyra, Lauren K; Stenesen, Drew et al. (2017) Stress-induced Cdk5 activity enhances cytoprotective basal autophagy in Drosophila melanogaster by phosphorylating acinus at serine437. Elife 6:
Tracy, Charles; Krämer, Helmut (2017) Escherichia coli Infection of Drosophila. Bio Protoc 7:
Casey, Amanda K; Moehlman, Andrew T; Zhang, Junmei et al. (2017) Fic-mediated deAMPylation is not dependent on homodimerization and rescues toxic AMPylation in flies. J Biol Chem 292:21193-21204
Tracy, Charles; Krämer, Helmut (2017) Isolation and Infection of Drosophila Primary Hemocytes. Bio Protoc 7:
Klionsky, Daniel J (see original citation for additional authors) (2016) Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition). Autophagy 12:1-222
Akbar, Mohammed Ali; Mandraju, Rajakumar; Tracy, Charles et al. (2016) ARC Syndrome-Linked Vps33B Protein Is Required for Inflammatory Endosomal Maturation and Signal Termination. Immunity 45:267-79
Stenesen, Drew; Moehlman, Andrew T; Krämer, Helmut (2015) The carcinine transporter CarT is required in Drosophila photoreceptor neurons to sustain histamine recycling. Elife 4:e10972
Nandi, Nilay; Tyra, Lauren K; Krämer, Helmut (2015) Activated Acinus boosts basal autophagy. Mol Cell Oncol 2:e995043

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