Integrative structural analysis of the human LRP2-LRPAP1 complex reveals multiple regulatory sites

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• The low-density lipoprotein receptor-related protein 2 (LRP2) is crucial for organ homeostasis.
• The interaction and regulatory role of LRPAP1 with LRP2 are not fully understood.
• Previous studies indicated single LRPAP1 binding to LRP2, leaving potential binding sites unoccupied.

Purpose of the Study:

• To investigate the binding stoichiometry of LRPAP1 to LRP2.
• To characterize the structural basis of LRPAP1-LRP2 interactions.
• To explore the functional and clinical implications of these interactions.

Main Methods:

• Integrative structural biology approach.
• Characterization of human recombinant LRP2 extracellular domain.
• Analysis of LRP2-LRPAP1 complex structure.

Main Results:

• Identification of three additional LRPAP1 binding sites on LRP2.
• Two new binding sites overlap with LRP2 ligand-binding regions.
• Discovery of unique LRPAP1-LRP2 interaction sites and pathogenic mutations at these interfaces.

Conclusions:

• LRPAP1 can bind LRP2 in multiple copies, suggesting a regulatory role.
• LRPAP1 binding may modulate LRP2's ligand-binding activity.
• The findings provide new insights into the functional and clinical significance of the LRPAP1-LRP2 interaction.