@article {737, title = {Lipid metabolic perturbation is an early-onset phenotype in adultmutants: amodel for lysosomal storage disorders. [Mass Spectrometry - Lipidomics]}, journal = {Mol Biol Cell}, volume = {28}, year = {2017}, month = {2017 Dec 15}, pages = {3728-3740}, abstract = {

Intracellular accumulation of lipids and swollen dysfunctional lysosomes are linked to several neurodegenerative diseases, including lysosomal storage disorders (LSD). Detailed characterization of lipid metabolic changes in relation to the onset and progression of neurodegeneration is currently missing. We systematically analyzed lipid perturbations inmutants, amodel of LSD-like neurodegeneration. Our results highlight an imbalance in brain ceramide and sphingosine in the early stages of neurodegeneration, preceding the accumulation of endomembranous structures, manifestation of altered behavior, and buildup of lipofuscin. Manipulating levels ofand altering these lipids inmutants allowed us to conclude that ceramide homeostasis is the driving force in disease progression and is integral tofunction in the adult nervous system. We identified 29 novel physical interaction partners of Spin and focused on the lipid carrier protein, Lipophorin (Lpp). A subset of Lpp and Spin colocalize in the brain and within organs specialized for lipid metabolism (fat bodies and oenocytes). Reduced Lpp protein was observed inmutant tissues. Finally, increased levels of lipid metabolites produced by oenocytes inmutants allude to a functional interaction between Spin and Lpp, underscoring the systemic nature of lipid perturbation in LSD.

}, keywords = {Animals, Carrier Proteins, Disease Models, Animal, Drosophila, Drosophila Proteins, Lipid Metabolism, Lipids, Lipoproteins, Lysosomal Storage Diseases, Lysosomes, Membrane Proteins, Mutation, Nervous System, Neurodegenerative Diseases, Phenotype}, issn = {1939-4586}, doi = {10.1091/mbc.E16-09-0674}, author = {Hebbar, Sarita and Khandelwal, Avinash and Jayashree, R and Hindle, Samantha J and Chiang, Yin Ning and Yew, Joanne Y and Sweeney, Sean T and Schwudke, Dominik} } @article {714, title = {Distinct spatial and molecular features of notch pathway assembly in regulatory T cells.}, journal = {Sci Signal}, volume = {5}, year = {2012}, month = {2012 Jul 24}, pages = {ra53}, abstract = {

Variations in the spatial localization of signaling components and crosstalk among signaling cascades are mechanisms through which diversity in signaling networks is generated. The receptor Notch provides an example of regulation by spatial localization: In the canonical Notch signaling pathway, Notch is cleaved to produce the Notch intracellular domain (NICD, also known as NIC), which translocates to the nucleus to regulate gene expression. We describe a T cell receptor-dependent, non-nuclear distribution and function of the processed receptor Notch, which was associated with the improved survival of regulatory T cells (T(regs)) in vitro and in vivo and was compromised by T cell-specific deletion of Notch1. Unlike a nuclear-restricted mutant of NICD, mutant NICD that underwent nuclear export or was targeted to the plasma membrane protected Notch1(-/-) T(regs) from apoptosis induced by nutrient deprivation and oxidative stress. Notch signaling integrated with phosphatidylinositol 3-kinase signaling and mammalian target of rapamycin complex 2 (mTORC2) for this cell survival function. Biochemical and imaging approaches revealed a membrane-proximal complex containing NICD and the mTORC2 component Rictor, and this complex was stabilized by specific interactions with the Notch ligand Delta-like-1 and mediated the survival of T(regs). Together, our evidence for the spatial control of Notch and the crosstalk of Notch signaling with other pathways reveals coupling between the localization of Notch and diverse intracellular signaling pathways.

}, keywords = {Animals, Apoptosis, Blotting, Western, Carrier Proteins, Cell Line, Cell Membrane, Cell Survival, Flow Cytometry, Gene Knockout Techniques, Humans, Immunoprecipitation, Intercellular Signaling Peptides and Proteins, Mice, Mice, Inbred C57BL, Microscopy, Fluorescence, Phosphatidylinositol 3-Kinase, Rapamycin-Insensitive Companion of mTOR Protein, Receptor Cross-Talk, Receptor, Notch1, Signal Transduction, T-Lymphocytes, Regulatory, Trans-Activators, Transcription Factors}, issn = {1937-9145}, doi = {10.1126/scisignal.2002859}, author = {Perumalsamy, Lakshmi R and Marcel, Nimi and Kulkarni, Sneha and Radtke, Freddy and Sarin, Apurva} } @article {479, title = {Interaction with a kinesin-2 tail propels choline acetyltransferase flow towards synapse. [Drosophila facility]}, journal = {Traffic}, volume = {13}, year = {2012}, month = {2012 Jul}, pages = {979-91}, abstract = {

Bulk flow constitutes a substantial part of the slow transport of soluble proteins in axons. Though the underlying mechanism is unclear, evidences indicate that intermittent, kinesin-based movement of large protein-aggregates aids this process. Choline acetyltransferase (ChAT), a soluble enzyme catalyzing acetylcholine synthesis, propagates toward the synapse at an intermediate, slow rate. The presynaptic enrichment of ChAT requires heterotrimeric kinesin-2, comprising KLP64D, KLP68D and DmKAP, in Drosophila. Here, we show that the bulk flow of a recombinant Green Fluorescent Protein-tagged ChAT (GFP::ChAT), in Drosophila axons, lacks particulate features. It occurs for a brief period during the larval stages. In addition, both the endogenous ChAT and GFP::ChAT directly bind to the KLP64D tail, which is essential for the GFP::ChAT entry and anterograde flow in axon. These evidences suggest that a direct interaction with motor proteins could regulate the bulk flow of soluble proteins, and thus establish their asymmetric distribution.

}, keywords = {Animals, Animals, Genetically Modified, Axonal Transport, Carrier Proteins, Choline O-Acetyltransferase, Cholinergic Neurons, Drosophila, Drosophila Proteins, Fluorescence Recovery After Photobleaching, Kinesin, Larva, Microtubule-Associated Proteins, Protein Interaction Domains and Motifs, Synapses}, issn = {1600-0854}, doi = {10.1111/j.1600-0854.2012.01361.x}, author = {Sadananda, Aparna and Hamid, Runa and Doodhi, Harinath and Ghosal, Debnath and Girotra, Mukul and Jana, Swadhin Chandra and Ray, Krishanu} }