Myosin light chain kinase accelerates vesicle endocytosis at the calyx of held synapse

Hai Yuan Yue, Jianhua Xu

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)295-304
Number of pages10
JournalJournal of Neuroscience
Volume34
Issue number1
DOIs
StatePublished - Jan 6 2014

Keywords

  • Capacitance
  • Endocytosis
  • Myosin
  • Myosin light chain kinase
  • The calyx of Held
  • Vesicle

ASJC Scopus subject areas

  • Neuroscience(all)

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