Crystal structure of ATP-bound Get3-Get4-Get5 complex reveals regulation of Get3 by Get4

Nat Struct Mol Biol. 2014 May;21(5):437-42. doi: 10.1038/nsmb.2813. Epub 2014 Apr 13.

Abstract

Correct localization of membrane proteins is essential to all cells. Chaperone cascades coordinate the capture and handover of substrate proteins from the ribosomes to the target membranes, yet the mechanistic and structural details of these processes remain unclear. Here we investigate the conserved GET pathway, in which the Get4-Get5 complex mediates the handover of tail-anchor (TA) substrates from the cochaperone Sgt2 to the Get3 ATPase, the central targeting factor. We present a crystal structure of a yeast Get3-Get4-Get5 complex in an ATP-bound state and show how Get4 primes Get3 by promoting the optimal configuration for substrate capture. Structure-guided biochemical analyses demonstrate that Get4-mediated regulation of ATP hydrolysis by Get3 is essential to efficient TA-protein targeting. Analogous regulation of other chaperones or targeting factors could provide a general mechanism for ensuring effective substrate capture during protein biogenesis.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases / chemistry*
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphate / chemistry*
  • Adenosine Triphosphate / metabolism
  • Amino Acid Sequence
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Crystallography, X-Ray
  • Gene Expression Regulation, Fungal
  • Guanine Nucleotide Exchange Factors / chemistry*
  • Guanine Nucleotide Exchange Factors / genetics
  • Membrane Proteins
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics
  • Ubiquitin / chemistry*
  • Ubiquitin / genetics

Substances

  • Carrier Proteins
  • GET4 protein, S cerevisiae
  • Guanine Nucleotide Exchange Factors
  • Mdy2 protein, S cerevisiae
  • Membrane Proteins
  • Saccharomyces cerevisiae Proteins
  • Ubiquitin
  • Adenosine Triphosphate
  • Adenosine Triphosphatases
  • Get3 protein, S cerevisiae

Associated data

  • PDB/4PWX