RESUMEN
Endophilin is a membrane-associated protein required for endocytosis of synaptic vesicles. Two models have been proposed for endophilin: that it alters lipid composition in order to shape membranes during endocytosis, or that it binds the polyphosphoinositide phosphatase synaptojanin and recruits this phosphatase to membranes. In this study, we demonstrate that the unc-57 gene encodes the Caenorhabditis elegans ortholog of endophilin A. We demonstrate that endophilin is required in C. elegans for synaptic vesicle recycling. Furthermore, the defects observed in endophilin mutants closely resemble those observed in synaptojanin mutants. The electrophysiological phenotype of endophilin and synaptojanin double mutants are virtually identical to the single mutants, demonstrating that endophilin and synaptojanin function in the same pathway. Finally, endophilin is required to stabilize expression of synaptojanin at the synapse. These data suggest that endophilin is an adaptor protein required to localize and stabilize synaptojanin at membranes during synaptic vesicle recycling.
Asunto(s)
Aciltransferasas/aislamiento & purificación , Caenorhabditis elegans/metabolismo , Endocitosis/genética , Proteínas del Tejido Nervioso/metabolismo , Monoéster Fosfórico Hidrolasas/metabolismo , Vesículas Sinápticas/metabolismo , Aciltransferasas/genética , Aciltransferasas/metabolismo , Animales , Caenorhabditis elegans/ultraestructura , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/aislamiento & purificación , Proteínas de Caenorhabditis elegans/metabolismo , ADN Complementario/análisis , ADN Complementario/genética , Microscopía Electrónica , Datos de Secuencia Molecular , Mutación/genética , Proteínas del Tejido Nervioso/genética , Monoéster Fosfórico Hidrolasas/genética , Terminales Presinápticos/metabolismo , Terminales Presinápticos/ultraestructura , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Membranas Sinápticas/genética , Membranas Sinápticas/metabolismo , Membranas Sinápticas/ultraestructura , Transmisión Sináptica/genética , Vesículas Sinápticas/ultraestructuraRESUMEN
The morphology of mitochondria is dynamic, often changing within a cell and from one cell type to the next. In the past few years, significant advances have been made in the study of mechanisms that help determine the morphologies of mitochondria and their intracellular distributions. It has become apparent that the distribution of mitochondria is determined by movement along the cytoskeleton, driven by molecular motors, and attachment to the cytoskeleton, using specific connector proteins. However, not all cells use the same cytoskeletal elements and motor proteins for mitochondrial movement and attachment. The shapes of mitochondria are also influenced by the extent of mitochondrial division and fusion. A number of proteins that affect mitochondrial division and fusion were recently discovered. Here, we review the proteins involved in the distribution and morphology of mitochondria and discuss how they may be physiologically regulated.