The structural basis of tail-anchored membrane protein recognition by Get3

Nature. 2009 Sep 17;461(7262):361-6. doi: 10.1038/nature08319. Epub 2009 Aug 12.

Abstract

Targeting of newly synthesized membrane proteins to the endoplasmic reticulum is an essential cellular process. Most membrane proteins are recognized and targeted co-translationally by the signal recognition particle. However, nearly 5% of membrane proteins are 'tail-anchored' by a single carboxy-terminal transmembrane domain that cannot access the co-translational pathway. Instead, tail-anchored proteins are targeted post-translationally by a conserved ATPase termed Get3. The mechanistic basis for tail-anchored protein recognition or targeting by Get3 is not known. Here we present crystal structures of yeast Get3 in 'open' (nucleotide-free) and 'closed' (ADP.AlF(4)(-)-bound) dimer states. In the closed state, the dimer interface of Get3 contains an enormous hydrophobic groove implicated by mutational analyses in tail-anchored protein binding. In the open state, Get3 undergoes a striking rearrangement that disrupts the groove and shields its hydrophobic surfaces. These data provide a molecular mechanism for nucleotide-regulated binding and release of tail-anchored proteins during their membrane targeting by Get3.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphatases / chemistry*
  • Adenosine Triphosphatases / metabolism*
  • Adenosine Triphosphate / metabolism
  • Aluminum Compounds / chemistry
  • Aluminum Compounds / metabolism
  • Crystallography, X-Ray
  • Fluorides / chemistry
  • Fluorides / metabolism
  • Guanine Nucleotide Exchange Factors / chemistry*
  • Guanine Nucleotide Exchange Factors / metabolism*
  • Hydrophobic and Hydrophilic Interactions
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Methanococcus
  • Models, Molecular
  • Protein Binding
  • Protein Conformation
  • Protein Multimerization
  • SEC Translocation Channels
  • Saccharomyces cerevisiae / chemistry*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Structure-Activity Relationship

Substances

  • Aluminum Compounds
  • Guanine Nucleotide Exchange Factors
  • Membrane Proteins
  • SEC Translocation Channels
  • Saccharomyces cerevisiae Proteins
  • tetrafluoroaluminate
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Adenosine Triphosphatases
  • Get3 protein, S cerevisiae
  • Fluorides

Associated data

  • PDB/2WOJ
  • PDB/2WOO