Structure of sorting nexin 11 (SNX11) reveals a novel extended phox homology (PX) domain critical for inhibition of SNX10-induced vacuolation

J Biol Chem. 2013 Jun 7;288(23):16598-16605. doi: 10.1074/jbc.M112.449306. Epub 2013 Apr 24.

Abstract

Sorting nexins are phox homology (PX) domain-containing proteins involved in diverse intracellular endosomal trafficking pathways. The PX domain binds to certain phosphatidylinositols and is recruited to vesicles rich in these lipids. The structure of the PX domain is highly conserved, containing a three-stranded β-sheet, followed by three α-helices. Here, we report the crystal structures of truncated human SNX11 (sorting nexin 11). The structures reveal that SNX11 contains a novel PX domain, hereby named the extended PX (PXe) domain, with two additional α-helices at the C terminus. We demonstrate that these α-helices are indispensible for the in vitro functions of SNX11. We propose that this PXe domain is present in SNX10 and is responsible for the vacuolation activity of SNX10. Thus, this novel PXe domain constitutes a structurally and functionally important PX domain subfamily.

Keywords: Cell Sorting; Endosome; PX Domain; PXe Domain; Phosphatidylinositol; Protein Sorting; Protein Structure; SNX10; SNX11; Sorting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • Phosphatidylinositols
  • Protein Binding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sorting Nexins / chemistry*
  • Sorting Nexins / genetics
  • Sorting Nexins / metabolism
  • Structure-Activity Relationship
  • Vacuoles*

Substances

  • Phosphatidylinositols
  • SNX10 protein, human
  • Sorting Nexins

Associated data

  • PDB/4IKB
  • PDB/4IKD