Structure of the Sgt2/Get5 complex provides insights into GET-mediated targeting of tail-anchored membrane proteins

Aline C. Simon, Peter J. Simpson, Rachael M. Goldstone, Ewelina M. Krysztofinska, James W. Murray, Stephen High, Rivka Isaacson

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Small, glutamine-rich, tetratricopeptide repeat protein 2 (Sgt2) is the first known port of call for many newly synthesized tail-anchored (TA) proteins released from the ribosome and destined for the GET (Guided Entry of TA proteins) pathway. This leads them to the residential membrane of the endoplasmic reticulum via an alternative to the cotranslational, signal recognition particle-dependent mechanism that their topology denies them. In yeast, the first stage of the GET pathway involves Sgt2 passing TA proteins on to the Get4/Get5 complex through a direct interaction between the N-terminal (NT) domain of Sgt2 and the ubiquitin-like (UBL) domain of Get5. Here we characterize this interaction at a molecular level by solving both a solution structure of Sgt2_NT, which adopts a unique helical fold, and a crystal structure of the Get5_UBL. Furthermore, using reciprocal chemical shift perturbation data and experimental restraints, we solve a structure of the Sgt2_NT/Get5_UBL complex, validate it via site-directed mutagenesis, and empirically determine its stoichiometry using relaxation experiments and isothermal titration calorimetry. Taken together, these data provide detailed structural information about the interaction between two key players in the coordinated delivery of TA protein substrates into the GET pathway.

Original languageEnglish
Pages (from-to)1327-1332
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number4
DOIs
Publication statusPublished - 22 Jan 2013

Keywords

  • GET4/GET5 COMPLEX
  • RICH TETRATRICOPEPTIDE REPEAT
  • BIOGENESIS
  • INSERTION
  • MECHANISM
  • macromolecular interactions
  • X-ray crystallography
  • INTERACTS
  • ASSIGNMENT
  • RECEPTOR
  • SGT2
  • NMR
  • DOMAINS

Fingerprint

Dive into the research topics of 'Structure of the Sgt2/Get5 complex provides insights into GET-mediated targeting of tail-anchored membrane proteins'. Together they form a unique fingerprint.

Cite this