@article {64958, title = {Evolution of Mechanisms that Control Mating in Drosophila Males.}, journal = {Cell Reports}, volume = {27}, year = {2019}, month = {2019 May 28}, pages = {2527-2536.e4}, abstract = {

Genetically wired neural mechanisms inhibit mating between species because even naive animals rarely mate with other species. These mechanisms can evolve through changes in expression or function of key genes in sensory pathways or central circuits. Gr32a is a gustatory chemoreceptor that, in D.\ melanogaster, is essential to inhibit interspecies courtship and sense quinine. Similar to D.\ melanogaster, we find that D.\ simulans Gr32a is expressed in foreleg tarsi, sensorimotor appendages that inhibit interspecies courtship, and it is required to sense quinine. Nevertheless, Gr32a is not required to inhibit interspecies mating by D.\ simulans males. However, and similar to its function in D.\ melanogaster, Ppk25, a member of the Pickpocket family, promotes conspecific courtship in D.\ simulans. Together, we have identified distinct evolutionary mechanisms underlying chemosensory control of taste and courtship in closely related Drosophila species.

}, issn = {2211-1247}, doi = {10.1016/j.celrep.2019.04.104}, author = {Ahmed, Osama M and Avila-Herrera, Aram and Tun, Khin May and Serpa, Paula H and Peng, Justin and Parthasarathy, Srinivas and Knapp, Jon-Michael and Stern, David L and Davis, Graeme W and Pollard, Katherine S and Shah, Nirao M} } @article {47284, title = {The innate immune receptor PGRP-LC controls presynaptic homeostatic plasticity.}, journal = {Neuron}, volume = {88}, year = {2015}, month = {2015 Dec 16}, pages = {1157-64}, abstract = {

It is now appreciated that the brain is immunologically active. Highly conserved innate immune signaling responds to pathogen invasion and injury and promotes structural refinement of neural circuitry. However, it remains generally unknown whether innate immune signaling has a function during the day-to-day regulation of neural function in the absence of pathogens and irrespective of cellular damage or developmental change. Here we show that an innate immune receptor, a member of the peptidoglycan pattern recognition receptor family (PGRP-LC), is required for the induction and sustained expression of homeostatic synaptic plasticity. This receptor functions presynaptically, controlling the homeostatic modulation of the readily releasable pool of synaptic vesicles following inhibition of postsynaptic glutamate receptor function. Thus, PGRP-LC is a candidate receptor for retrograde, trans-synaptic signaling, a novel activity for innate immune signaling and the first known function of a PGRP-type receptor in the nervous system of any organism.

}, issn = {1097-4199}, doi = {10.1016/j.neuron.2015.10.049}, author = {Harris, Nathan and Braiser, Daniel J and Dickman, Dion K and Fetter, Richard D and Tong, Amy and Davis, Graeme W} } @article {46425, title = {Glial-derived prodegenerative signaling in the Drosophila neuromuscular system.}, journal = {Neuron}, volume = {72}, year = {2011}, month = {2011 Dec 8}, pages = {760-75}, abstract = {

We provide evidence for a prodegenerative, glial-derived signaling framework in the Drosophila neuromuscular system that includes caspase and mitochondria-dependent signaling. We demonstrate that Drosophila TNF-α (eiger) is expressed in a subset of peripheral glia, and the TNF-α receptor (TNFR), Wengen, is expressed in motoneurons. NMJ degeneration caused by disruption of the spectrin/ankyrin skeleton is suppressed by an eiger mutation or by eiger knockdown within a subset of peripheral glia. Loss of wengen in motoneurons causes a similar suppression providing evidence for glial-derived prodegenerative TNF-α signaling. Neither JNK nor NFκβ is required for prodegenerative signaling. However, we provide evidence for the involvement of both an initiator and effector caspase, Dronc and Dcp-1, and mitochondrial-dependent signaling. Mutations that deplete the axon and nerve terminal of mitochondria suppress degeneration as do mutations in Drosophila Bcl-2 (debcl), a mitochondria-associated protein, and Apaf-1 (dark), which links mitochondrial signaling with caspase activity in other systems.

}, keywords = {Animals, Animals, Genetically Modified, Apoptotic Protease-Activating Factor 1, Caspases, Disease Models, Animal, Drosophila, Drosophila Proteins, Excitatory Postsynaptic Potentials, Fluorescence Recovery After Photobleaching, Green Fluorescent Proteins, Mitochondria, Motor Neuron Disease, Mutation, Nerve Degeneration, Nerve Tissue Proteins, Neuroglia, Neuromuscular Junction, Proto-Oncogene Proteins, Receptors, Tumor Necrosis Factor, RNA Interference, Signal Transduction}, issn = {1097-4199}, doi = {10.1016/j.neuron.2011.09.031}, author = {Keller, Lani C and Cheng, Ling and Locke, Cody J and M{\"u}ller, Martin and Fetter, Richard D and Davis, Graeme W} } @article {46424, title = {Hts/Adducin controls synaptic elaboration and elimination.}, journal = {Neuron}, volume = {69}, year = {2011}, month = {2011 Mar 24}, pages = {1114-31}, abstract = {

Neural development requires both synapse elaboration and elimination, yet relatively little is known about how these opposing activities are coordinated. Here, we provide evidence Hts/Adducin can serve this function. We show that Drosophila Hts/Adducin is enriched both pre- and postsynaptically at the NMJ. We then demonstrate that presynaptic Hts/Adducin is necessary and sufficient to control two opposing processes associated with synapse remodeling: (1) synapse stabilization as determined by light level and ultrastructural and electrophysiological assays and (2) the elaboration of actin-based, filopodia-like protrusions that drive synaptogenesis and growth. Synapse remodeling is sensitive to Hts/Adducin levels, and we provide evidence that the synaptic localization of Hts/Adducin is controlled via phosphorylation. Mechanistically, Drosophila Hts/Adducin protein has actin-capping activity. We propose that phosphorylation-dependent regulation of Hts/Adducin controls the level, localization, and activity of Hts/Adducin, influencing actin-based synapse elaboration and spectrin-based synapse stabilization. Hts/Adducin may define a mechanism to switch between synapse stability and dynamics.

}, keywords = {Actins, Animals, Animals, Genetically Modified, Biological Transport, Blotting, Western, Calmodulin-Binding Proteins, Cytoskeleton, Drosophila, Drosophila Proteins, Electrophysiology, Immunohistochemistry, Microscopy, Electron, Transmission, Phosphorylation, Spectrin, Synapses, Synaptic Transmission}, issn = {1097-4199}, doi = {10.1016/j.neuron.2011.02.007}, author = {Pielage, Jan and Bulat, Victoria and Zuchero, J Bradley and Fetter, Richard D and Davis, Graeme W} } @article {46422, title = {Negative regulation of active zone assembly by a newly identified SR protein kinase.}, journal = {PLoS Biology}, volume = {7}, year = {2009}, month = {2009 Sep}, pages = {e1000193}, abstract = {

Presynaptic, electron-dense, cytoplasmic protrusions such as the T-bar (Drosophila) or ribbon (vertebrates) are believed to facilitate vesicle movement to the active zone (AZ) of synapses throughout the nervous system. The molecular composition of these structures including the T-bar and ribbon are largely unknown, as are the mechanisms that specify their synapse-specific assembly and distribution. In a large-scale, forward genetic screen, we have identified a mutation termed air traffic controller (atc) that causes T-bar-like protein aggregates to form abnormally in motoneuron axons. This mutation disrupts a gene that encodes for a serine-arginine protein kinase (SRPK79D). This mutant phenotype is specific to SRPK79D and is not secondary to impaired kinesin-dependent axonal transport. The srpk79D gene is neuronally expressed, and transgenic rescue experiments are consistent with SRPK79D kinase activity being necessary in neurons. The SRPK79D protein colocalizes with the T-bar-associated protein Bruchpilot (Brp) in both the axon and synapse. We propose that SRPK79D is a novel T-bar-associated protein kinase that represses T-bar assembly in peripheral axons, and that SRPK79D-dependent repression must be relieved to facilitate site-specific AZ assembly. Consistent with this model, overexpression of SRPK79D disrupts AZ-specific Brp organization and significantly impairs presynaptic neurotransmitter release. These data identify a novel AZ-associated protein kinase and reveal a new mechanism of negative regulation involved in AZ assembly. This mechanism could contribute to the speed and specificity with which AZs are assembled throughout the nervous system.

}, keywords = {Animals, Drosophila melanogaster, Drosophila Proteins, Immunohistochemistry, Microscopy, Electron, Transmission, Motor Neurons, Presynaptic Terminals, Protein-Serine-Threonine Kinases, Synaptic Transmission}, issn = {1545-7885}, doi = {10.1371/journal.pbio.1000193}, author = {Johnson, Ervin L and Fetter, Richard D and Davis, Graeme W} } @article {46416, title = {Clathrin dependence of synaptic-vesicle formation at the Drosophila neuromuscular junction.}, journal = {Current Biology}, volume = {18}, year = {2008}, month = {2008 Mar 25}, pages = {401-9}, abstract = {

BACKGROUND: Among the most prominent molecular constituents of a recycling synaptic vesicle is the clathrin triskelion, composed of clathrin light chain (Clc) and clathrin heavy chain (Chc). Remarkably, it remains unknown whether clathrin is strictly necessary for the stimulus-dependent re-formation of a synaptic vesicle and, conversely, whether clathrin-independent vesicle endocytosis exists at the neuronal synapse.

RESULTS: We employ FlAsH-FALI-mediated protein photoinactivation to rapidly (3 min) and specifically disrupt Clc function at the Drosophila neuromuscular junction. We first demonstrate that Clc photoinactivation does not impair synaptic-vesicle fusion. We then provide electrophysiological and ultrastructural evidence that synaptic vesicles, once fused with the plasma membrane, cannot be re-formed after Clc photoinactivation. Finally, we demonstrate that stimulus-dependent membrane internalization occurs after Clc photoinactivation. However, newly internalized membrane fails to resolve into synaptic vesicles. Rather, newly internalized membrane forms large and extensive internal-membrane compartments that are never observed at a wild-type synapse.

CONCLUSIONS: We make three major conclusions. (1) FlAsH-FALI-mediated protein photoinactivation rapidly and specifically disrupts Clc function with no effect on synaptic-vesicle fusion. (2) Synaptic-vesicle re-formation does not occur after Clc photoinactivation. By extension, clathrin-independent "kiss-and-run" endocytosis does not sustain synaptic transmission during a stimulus train at this synapse. (3) Stimulus-dependent, clathrin-independent membrane internalization exists at this synapse, but it is unable to generate fusion-competent, small-diameter synaptic vesicles.

}, keywords = {Animals, Clathrin Light Chains, Drosophila, Electrophysiology, Endocytosis, Fluoresceins, Larva, Neuromuscular Junction, Organometallic Compounds, Synaptic Membranes, Synaptic Transmission, Synaptic Vesicles}, issn = {0960-9822}, doi = {10.1016/j.cub.2008.02.055}, author = {Heerssen, Heather and Fetter, Richard D and Davis, Graeme W} } @article {46419, title = {A presynaptic giant ankyrin stabilizes the NMJ through regulation of presynaptic microtubules and transsynaptic cell adhesion.}, journal = {Neuron}, volume = {58}, year = {2008}, month = {2008 Apr 24}, pages = {195-209}, abstract = {

In a forward genetic screen for mutations that destabilize the neuromuscular junction, we identified a novel long isoform of Drosophila ankyrin2 (ank2-L). We demonstrate that loss of presynaptic Ank2-L not only causes synapse disassembly and retraction but also disrupts neuronal excitability and NMJ morphology. We provide genetic evidence that ank2-L is necessary to generate the membrane constrictions that normally separate individual synaptic boutons and is necessary to achieve the normal spacing of subsynaptic protein domains, including the normal organization of synaptic cell adhesion molecules. Mechanistically, synapse organization is correlated with a lattice-like organization of Ank2-L, visualized using extended high-resolution structured-illumination microscopy. The stabilizing functions of Ank2-L can be mapped to the extended C-terminal domain that we demonstrate can directly bind and organize synaptic microtubules. We propose that a presynaptic Ank2-L lattice links synaptic membrane proteins and spectrin to the underlying microtubule cytoskeleton to organize and stabilize the presynaptic terminal.

}, keywords = {Amino Acid Motifs, Animals, Animals, Genetically Modified, Ankyrins, Cell Adhesion Molecules, Neuronal, Drosophila, Drosophila Proteins, Gene Expression Regulation, Horseradish Peroxidase, Larva, Luminescent Proteins, Microscopy, Electron, Transmission, Microtubules, Mutation, Neuromuscular Junction, Presynaptic Terminals, Synapsins, Synaptic Transmission}, issn = {1097-4199}, doi = {10.1016/j.neuron.2008.02.017}, author = {Pielage, Jan and Cheng, Ling and Fetter, Richard D and Carlton, Pete M and Sedat, John W and Davis, Graeme W} } @article {46427, title = {NF-κB, IκB, and IRAK control glutamate receptor density at the Drosophila NMJ.}, journal = {Neuron}, volume = {55}, year = {2007}, month = {2007 Sep 20}, pages = {859-73}, abstract = {

NF-κB signaling has been implicated in neurodegenerative disease, epilepsy, and neuronal plasticity. However, the cellular and molecular activity of NF-κB signaling within the nervous system remains to be clearly defined. Here,\ we show that the NF-κB and IκB homologs Dorsal and Cactus surround postsynaptic glutamate receptor (GluR) clusters at the Drosophila\ NMJ. We then show that mutations in dorsal, cactus, and IRAK/pelle kinase specifically impair GluR levels, assayed immunohistochemically and electrophysiologically, without affecting NMJ growth, the size of the postsynaptic density, or homeostatic plasticity. Additional genetic experiments support the conclusion that cactus functions in concert with, rather than in opposition to, dorsal and pelle in this process. Finally, we provide evidence that Dorsal and Cactus act\ posttranscriptionally, outside the nucleus, to control GluR density. Based upon our data we speculate that Dorsal, Cactus, and Pelle could function together, locally at the postsynaptic density, to specify GluR levels.

}, keywords = {Developmental Biology, molecular neurology, signaling}, doi = {10.1016/j.neuron.2007.08.005}, author = {Heckscher, Elizabeth S and Fetter, Richard D and Marek, Kurt W and Albin, Stephanie D and Davis, Graeme W} }