Structure of human mitochondrial pyruvate carrier MPC1 and MPC2 complex

Area of Science:

• Biochemistry
• Structural Biology
• Cellular Metabolism

Background:

• The Mitochondrial Pyruvate Carrier (MPC) is crucial for linking glycolysis to mitochondrial respiration.
• MPC facilitates pyruvate transport into mitochondria, supporting ATP production and biosynthesis.
• The MPC complex is a heterodimer of MPC1 and MPC2 subunits.

Purpose of the Study:

• To determine the high-resolution structures of the human MPC1-2 complex.
• To elucidate the mechanisms of pyruvate transport and inhibitor binding.
• To understand the structural basis of MPC function and regulation.

Main Methods:

• Cryogenic electron microscopy (cryo-EM) to resolve human MPC1-2 structures.
• Biochemical analysis of inhibitor binding and substrate interactions.
• Yeast rescue assays to validate functional consequences of mutations.

Main Results:

• Cryo-EM structures of human MPC1-2 in IMS-open and matrix-open states were obtained.
• The transport channel is formed by specific transmembrane helix interactions between MPC1 and MPC2.
• The inhibitor UK5099 binds at the matrix side, stabilizing the matrix-open conformation.
• A W82F mutation in MPC2 locks the complex in an IMS-open conformation.

Conclusions:

• Structural insights into MPC conformations provide a mechanistic understanding of pyruvate transport.
• The study reveals how MPC inhibitors function by stabilizing specific conformational states.
• Mutations can alter MPC conformation, impacting its role in cellular metabolism.