Structural Basis for Rab8a Recruitment of RILPL2 via LRRK2 Phosphorylation of Switch 2

Structure. 2020 Apr 7;28(4):406-417.e6. doi: 10.1016/j.str.2020.01.005. Epub 2020 Feb 3.

Abstract

Rab8a is associated with the dynamic regulation of membrane protrusions in polarized cells. Rab8a is one of several Rab GTPases that are substrates of leucine-rich repeat kinase 2 (LRRK2), a serine/threonine kinase that is linked to Parkinson's disease. Rab8a is phosphorylated at T72 (pT72) in its switch 2 helix and recruits the phospho-specific effector RILPL2, which subsequently regulates ciliogenesis. Here, we report the crystal structure of phospho-Rab8a (pRab8a) in complex with the RH2 (RILP homology) domain of RILPL2. The complex is a heterotetramer with RILPL2 forming a central α-helical dimer that bridges two pRab8a molecules. The N termini of the α helices cross over, forming an X-shaped cap (X-cap) that orients Arg residues from RILPL2 toward pT72. X-cap residues critical for pRab8a binding are conserved in JIP3 and JIP4, which also interact with LRRK2-phosphorylated Rab10. We propose a general mode of recognition for phosphorylated Rab GTPases by this family of phospho-specific effectors.

Keywords: JNK-interacting protein 3 and 4; LRRK2 kinase; RILP-like protein 2; Rab8a GTPase; effector; membrane trafficking.

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

  • Adaptor Proteins, Signal Transducing / chemistry*
  • Adaptor Proteins, Signal Transducing / metabolism
  • Binding Sites
  • HEK293 Cells
  • Humans
  • Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 / metabolism
  • Molecular Docking Simulation
  • Phosphorylation
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • rab GTP-Binding Proteins / chemistry*
  • rab GTP-Binding Proteins / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Rilpl2 protein, mouse
  • LRRK2 protein, human
  • Leucine-Rich Repeat Serine-Threonine Protein Kinase-2
  • RAB8A protein, human
  • rab GTP-Binding Proteins