A5015799919- Cellular transport and secretion
- Autophagy in Disease and Therapy
- Lysosomal Storage Disorders Research
- Molecular Biology Techniques and Applications
- Protein Kinase Regulation and GTPase Signaling
- RNA Research and Splicing
- Invertebrate Immune Response Mechanisms
- Genetics, Aging, and Longevity in Model Organisms
- Developmental Biology and Gene Regulation
- Calcium signaling and nucleotide metabolism
- Ubiquitin and proteasome pathways
- Retinal Development and Disorders
- CRISPR and Genetic Engineering
- Sperm and Testicular Function
- Cellular Mechanics and Interactions
- Photosynthetic Processes and Mechanisms
- Lipid Membrane Structure and Behavior
- Microtubule and mitosis dynamics
- Endoplasmic Reticulum Stress and Disease
- Animal Genetics and Reproduction
- Biocrusts and Microbial Ecology
- Extracellular vesicles in disease
- Xenotransplantation and immune response
- Religion, Spirituality, and Psychology
- Ion channel regulation and function
University of California, San Diego
2008-2020
Harvard University
2002-2004
Max Planck Institute for Molecular Genetics
2004
Howard Hughes Medical Institute
2002-2004
Harvard University Press
2004
Stanford University
1999
A crucial aim upon completion of whole genome sequences is the functional analysis all predicted genes. We have applied a high-throughput RNA-interference (RNAi) screen 19,470 double-stranded (ds) RNAs in cultured cells to characterize function nearly (91%) Drosophila genes cell growth and viability. found 438 dsRNAs that identified essential genes, among which 80% lacked mutant alleles. quantitative assay number was identify known uncharacterized functions. In particular, we demonstrate...
Stem cells generate many differentiated, short-lived cell types, such as blood, skin, and sperm, throughout adult life. maintain a long-term capacity to divide, producing daughter that either self-renew or initiate differentiation. Although the surrounding microenvironment “niche” influences stem fate decisions, few signals emanate from niche specify self-renewal have been identified. Here we demonstrate apical hub in Drosophila testis act cellular supports self-renewal. Hub express ligand...
Cytokinesis involves temporally and spatially coordinated action of the cell cycle cytoskeletal membrane systems to achieve separation daughter cells. To dissect cytokinesis mechanisms it would be useful have a complete catalog proteins involved, small molecule tools for specifically inhibiting them with tight temporal control. Finding active molecules by cell-based screening entails difficult step identifying their targets. We performed parallel chemical genetic genome-wide RNA interference...
Abstract Male gametes are produced throughout reproductive life by a classic stem cell mechanism. However, little is known about the molecular mechanisms for lineage production that maintain male germ-line (GSC) populations, regulate mitotic amplification divisions, and ensure germ differentiation. Here we utilize Drosophila system to identify genes cause defects in GSC when forcibly expressed. We conducted gain-of-function screen using collection of 2050 EP lines found 55 caused at early...
Transverse (T)-tubules make-up a specialized network of tubulated muscle cell membranes involved in excitation-contraction coupling for power contraction. Little is known about how T-tubules maintain highly organized structures and contacts throughout the contractile system despite ongoing remodeling that occurs with atrophy, damage aging. We uncovered an essential role autophagy T-tubule genetic screens developmentally regulated program Drosophila abdominal muscles. Here, we show both...
Reversible phosphoinositide phosphorylation provides a dynamic membrane code that balances opposing cell functions. However, in vivo regulatory relationships between specific kinases, phosphatases, and subpools are not clear. We identified myotubularin (mtm), Drosophila melanogaster MTM1/MTMR2 phosphatase, as necessary sufficient for immune protrusion formation recruitment to wounds. Mtm-mediated turnover of endosomal phosphatidylinositol 3-phosphate (PI(3)P) pools generated by both class II...
Muscles must maintain cell compartmentalization when remodeled during development and use. How spatially restricted adhesions are regulated with muscle remodeling is largely unexplored. We show that the myotubularin (mtm) phosphoinositide phosphatase required for integrin-mediated myofiber attachments in Drosophila melanogaster, mtm-depleted myofibers exhibit hallmarks of human XLMTM myopathy. Depletion mtm leads to increased integrin turnover at sarcolemma an accumulation PI(3)P on...
Cells rely on the coordinated regulation of lipid phosphoinositides and Rab GTPases to define membrane compartment fates along distinct trafficking routes. The family disease-related myotubularin (MTM) phosphoinositide phosphatases includes catalytically inactive members, or pseudophosphatases, with poorly understood functions. We found that Drosophila MTM pseudophosphatase Sbf coordinates both phosphatidylinositol 3-phosphate (PI(3)P) turnover Rab21 GTPase activation in an endosomal pathway...
Dynamic regulation of cell shape underlies many developmental and immune functions. Cortical remodeling is achieved under the central control Rho GTPase pathways that modulate an exquisite balance in dynamic assembly disassembly cytoskeleton focal adhesions. Macroautophagy (autophagy), associated with bulk cytoplasmic through lysosomal degradation, has clearly defined roles survival death. Moreover, it becoming apparent proteins, organelles, pathogens can be targeted for autophagic clearance...
Although a large number of actin-binding proteins and their regulators have been identified through classical approaches, gaps in our knowledge remain. Here, we used genome-wide RNA interference as systematic method to define metazoan actin based on visual phenotype. Using comparative screens cultured Drosophila human cells, generated phenotypic profiles for annotated together with bearing predicted domains. These clusters the known "actinome" were identify putative new core regulators,...
Lamellipodia are broad actin-based structures that define the protruding edge of many motile animal cells. Here we identify a Drosophila homolog p21-activated kinases (Paks) as novel inhibitor Rac-mediated lamellipodial formation: Pak3 overexpression mimics loss Rac activity, while RNAi-mediated silencing enhances dynamics. Strikingly, depletion also polarizes cellular distribution actin filaments, is sufficient to induce nonmotile cells migrate, and, in firmly attached substrate, gives rise...
ABSTRACT Lysosomes are compartments for the degradation of both endocytic and autophagic cargoes. The shape lysosomes changes with cellular degradative demands; however, there is limited knowledge about mechanisms or significance that underlies distinct lysosomal morphologies. Here, we found an extensive tubular autolysosomal network in Drosophila abdominal muscle remodeling during metamorphosis. transiently appeared exhibited capacity to degrade was uniquely marked by SNARE protein...
The Atg1 Ser/Thr kinase, although now a well-established regulator of autophagy, was first identified genetically in C. elegans as requirement for axonal elongation. However, possible connections between functions cellular morphogenesis and autophagy were previously unaddressed. In the recent paper highlighted this punctum, we reconciled these dual roles Atg1, demonstrating p62-mediated selective dynamic regulation cell shape, both fly mammalian macrophages, with effects on immune functions....
Abstract Drosophila nup154 encodes a predicted nucleoporin homologous to yeast Nup170p, Nup157p, and vertebrate Nup155, all of which are major components the nuclear pore complex (NPC). Unlike its homologs, is essential for viability. Animals with strong loss-of-function mutations caused by P-element insertion in 5′-UTR gene died as larvae small discs, brains, testes. mRNA expression appeared developmentally regulated tissues wild-type embryos, larvae, adults, suggesting that new synthesis...
The Rab family of small GTPases are essential regulators membrane trafficking events. As with other GTPase families, cycle between an inactive GDP- bound state and active GTP-bound state. Guanine nucleotide exchange factors (GEFs) promote activation the GDP for GTP, while GTPase-activating proteins (GAPs) regulate inactivation GTP hydrolysis. Numerous methods have been established to monitor status GTPases. Of those, FRET-based used identify when where a is activated in cells. Unfortunately,...
Transmembrane proteins are rarely exclusively localized to a specific vesicle or an organelle. Most transmembrane undergo complicated trafficking routes. Thus, under constant flux, and at steady state, found on variety of vesicles organelles. This characteristic makes the study their routes complex, since any given moment, different molecules often being trafficked in opposing directions. Pulse-chase experiments can temporally track pool protein interest, allowing for kinetic description its...
Transverse (T)-tubules - vast, tubulated domains of the muscle plasma membrane are critical to maintain healthy skeletal and heart contractions. How intricate T-tubule membranes formed is not well understood, with challenges systematically interrogate in muscle. We established use intact Drosophila larval body wall muscles as an ideal system discover mechanisms that sculpt network. A muscle-targeted genetic screen identified specific phosphoinositide lipid regulators necessary for...