Myosin Light Chain Kinase Accelerates Vesicle Endocytosis at the Calyx of Held Synapse
| Autor: | Jianhua Xu, Hai Yuan Yue |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Male
Myosin light-chain kinase Calmodulin Endocytic cycle macromolecular substances Endocytosis Exocytosis Bulk endocytosis Rats Sprague-Dawley Organ Culture Techniques Animals Enzyme Inhibitors Myosin-Light-Chain Kinase biology Chemistry General Neuroscience Articles Receptor-mediated endocytosis Rats Cell biology Synapses biology.protein Female Synaptic Vesicles Calyx of Held Brain Stem |
| Zdroj: | The Journal of Neuroscience. 34:295-304 |
| ISSN: | 1529-2401 0270-6474 |
| DOI: | 10.1523/jneurosci.3744-13.2014 |
| Popis: | Neuronal activity triggers endocytosis at synaptic terminals to retrieve efficiently the exocytosed vesicle membrane, ensuring the membrane homeostasis of active zones and the continuous supply of releasable vesicles. The kinetics of endocytosis depends on Ca2+and calmodulin which, as a versatile signal pathway, can activate a broad spectrum of downstream targets, including myosin light chain kinase (MLCK). MLCK is known to regulate vesicle trafficking and synaptic transmission, but whether this kinase regulates vesicle endocytosis at synapses remains elusive. We investigated this issue at the rat calyx of Held synapse, where previous studies using whole-cell membrane capacitance measurement have characterized two common forms of Ca2+/calmodulin-dependent endocytosis, i.e., slow clathrin-dependent endocytosis and rapid endocytosis. Acute inhibition of MLCK with pharmacological agents was found to slow down the kinetics of both slow and rapid forms of endocytosis at calyces. Similar impairment of endocytosis occurred when blocking myosin II, a motor protein that can be phosphorylated upon MLCK activation. The inhibition of endocytosis was not accompanied by a change in Ca2+channel current. Combined inhibition of MLCK and calmodulin did not induce synergistic inhibition of endocytosis. Together, our results suggest that activation of MLCK accelerates both slow and rapid forms of vesicle endocytosis at nerve terminals, likely by functioning downstream of Ca2+/calmodulin. |
| Databáze: | OpenAIRE |
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