Clathrin light chain diversity regulates membrane deformation in vitro and synaptic vesicle formation in vivo

Proc Natl Acad Sci U S A. 2020 Sep 22;117(38):23527-23538. doi: 10.1073/pnas.2003662117. Epub 2020 Sep 9.

Abstract

Clathrin light chain (CLC) subunits in vertebrates are encoded by paralogous genes CLTA and CLTB, and both gene products are alternatively spliced in neurons. To understand how this CLC diversity influences neuronal clathrin function, we characterized the biophysical properties of clathrin comprising individual CLC variants for correlation with neuronal phenotypes of mice lacking either CLC-encoding gene. CLC splice variants differentially influenced clathrin knee conformation within assemblies, and clathrin with neuronal CLC mixtures was more effective in membrane deformation than clathrin with single neuronal isoforms nCLCa or nCLCb. Correspondingly, electrophysiological recordings revealed that neurons from mice lacking nCLCa or nCLCb were both defective in synaptic vesicle replenishment. Mice with only nCLCb had a reduced synaptic vesicle pool and impaired neurotransmission compared to WT mice, while nCLCa-only mice had increased synaptic vesicle numbers, restoring normal neurotransmission. These findings highlight differences between the CLC isoforms and show that isoform mixing influences tissue-specific clathrin activity in neurons, which requires their functional balance.

Keywords: clathrin; coated vesicle formation; membrane traffic; neuronal synapse; protein isoforms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CA1 Region, Hippocampal / cytology
  • CA1 Region, Hippocampal / metabolism
  • Cells, Cultured
  • Clathrin Light Chains* / chemistry
  • Clathrin Light Chains* / genetics
  • Clathrin Light Chains* / metabolism
  • Mice
  • Mice, Knockout
  • Neurons / cytology
  • Neurons / metabolism
  • Protein Isoforms / chemistry
  • Protein Isoforms / metabolism
  • Synaptic Vesicles / chemistry*
  • Synaptic Vesicles / metabolism*

Substances

  • Clathrin Light Chains
  • Protein Isoforms