Journal Article

Cryo-EM structure of the Hippo signaling integrator human STRIPAK

Luo, Xuelian, Bae, Sung Jun, Bai, Xiao-chen, Zhang, Xuewu, Jeong, Byung-Cheon, Ni, Lisheng

2021

Overview

The striatin-interacting phosphatase and kinase (STRIPAK) complex is a large, multisubunit protein phosphatase 2A (PP2A) assembly that integrates diverse cellular signals in the Hippo pathway to regulate cell proliferation and survival. The architecture and assembly mechanism of this critical complex are poorly understood. Using cryo-EM, we determine the structure of the human STRIPAK core comprising PP2AA, PP2AC, STRN3, STRIP1, and MOB4 at 3.2-Å resolution. Unlike the canonical trimeric PP2A holoenzyme, STRIPAK contains four copies of STRN3 and one copy of each the PP2AA–C heterodimer, STRIP1, and MOB4. The STRN3 coiled-coil domains form an elongated homotetrameric scaffold that links the complex together. An inositol hexakisphosphate (IP 6 ) is identified as a structural cofactor of STRIP1. Mutations of key residues at subunit interfaces disrupt the integrity of STRIPAK, causing aberrant Hippo pathway activation. Thus, STRIPAK is established as a noncanonical PP2A complex with four copies of regulatory STRN3 for enhanced signal integration. A cryo-EM structure of the striatin-interacting phosphatase and kinase (STRIPAK) complex reveals the overall architecture of this large, multisubunit assembly that broadly regulates different signaling pathways.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: 631/45/607 / 631/535/1258/1259 / 631/57 / Adaptor Proteins, Signal Transducing - chemistry / Adaptor Proteins, Signal Transducing - genetics / Adaptor Proteins, Signal Transducing - metabolism / Assembly / Autoantigens - chemistry / Autoantigens - genetics / Autoantigens - metabolism / Autoantigens - ultrastructure / Biochemistry / Biological Microscopy / Biomedical and Life Sciences / Calmodulin-Binding Proteins - chemistry / Calmodulin-Binding Proteins - genetics / Calmodulin-Binding Proteins - metabolism / Calmodulin-Binding Proteins - ultrastructure / Cell proliferation / Cell survival / Coils / Coils (strip) / Cryoelectron Microscopy / Hippo Signaling Pathway / Humans / Inositol / Interfaces / Kinases / Life Sciences / Membrane Biology / Models, Molecular / Multienzyme Complexes - chemistry / Multienzyme Complexes - genetics / Multienzyme Complexes - metabolism / Multienzyme Complexes - ultrastructure / Mutation / Phosphatase / Phosphate-Binding Proteins - chemistry / Phosphate-Binding Proteins - genetics / Phosphate-Binding Proteins - metabolism / Phosphate-Binding Proteins - ultrastructure / Phosphoprotein phosphatase / Phytic Acid - metabolism / Protein Multimerization / Protein phosphatase / Protein Phosphatase 2 - chemistry / Protein Phosphatase 2 - genetics / Protein Phosphatase 2 - metabolism / Protein Phosphatase 2 - ultrastructure / Protein Serine-Threonine Kinases - chemistry / Protein Serine-Threonine Kinases - metabolism / Protein Structure / Protein Subunits - chemistry / Protein Subunits - genetics / Protein Subunits - metabolism / Signal Transduction / Signaling