Comparative analysis of adaptor-mediated clathrin assembly reveals general principles for adaptor clustering

Mol Biol Cell. 2016 Oct 15;27(20):3156-3163. doi: 10.1091/mbc.E16-06-0399. Epub 2016 Aug 24.

Abstract

Clathrin-mediated endocytosis (CME) manages the sorting and uptake of the bulk of membrane proteins (or cargo) from the plasma membrane. CME is initiated by the formation of clathrin-coated pits (CCPs), in which adaptors nucleate clathrin assembly. Clathrin adaptors display diversity in both the type and number of evolutionarily conserved clathrin-binding boxes. How this diversity relates to the process of adaptor clustering as clathrin assembles around a growing pit remains unclear. Using real-time, fluorescence microscopy-based assays, we compare the formation kinetics and distribution of clathrin assemblies on membranes that display five unique clathrin adaptors. Correlations between equilibrium and kinetic parameters of clathrin assembly to the eventual adaptor distribution indicate that adaptor clustering is determined not by the amount of clathrin recruited or the degree of clathrin clustered but instead by the rate of clathrin assembly. Together our results emphasize the need to analyze kinetics of protein interactions to better understand mechanisms that regulate CME.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / metabolism*
  • Adaptor Proteins, Vesicular Transport / physiology
  • Animals
  • Cell Membrane / metabolism
  • Clathrin / metabolism
  • Clathrin-Coated Vesicles / metabolism*
  • Coated Pits, Cell-Membrane / metabolism
  • Endocytosis / physiology
  • Humans
  • Kinetics
  • Membrane Proteins / metabolism
  • Optical Imaging / methods
  • Protein Binding
  • Protein Transport / physiology

Substances

  • Adaptor Proteins, Vesicular Transport
  • Clathrin
  • Membrane Proteins