Characterization of cis-Autoproteolysis of Polycystin-1, the Product of Human Polycystic Kidney Disease 1 Gene

Wen Wei,Feng Qian,Gregory Germino,Karl Hackmann,Hangxue Xu

doi:10.1074/jbc.m703218200

Abstract

Polycystin-1 (PC1), the PKD1 gene product, plays a critical role in renal tubule diameter control and disruption of its function causes cyst formation in human autosomal dominant polycystic kidney disease. Recent evidence shows that PC1 undergoes cleavage at the juxtamembrane G protein-coupled receptor proteolytic site (GPS), a process likely to be essential for its biological activity. Here we further characterized the proteolytic cleavage of PC1 at the GPS domain. We determined the actual cleavage site to be between leucine and threonine of the tripeptide HLT(3049) of human PC1. Cleavage occurs in the early intracellular secretory pathway and requires initial N-glycan attachment but not its subsequent trimming. We provide evidence that the cleavage occurs via a cis-autoproteolytic mechanism involving an ester intermediate as shown for Ntn hydrolases and EMR2.

Highlights

PC1 is thought to function as a cell surface signaling receptor at cell-cell/cell-matrix junctions and as a mechano-sensor in renal primary cilia that activates signaling pathways involved in renal tubular differentiation [2,3,4]
We have provided evidence that PC1 is cleaved at the G protein-coupled receptor proteolytic site (GPS) domain through a similar cis-autoproteolytic mechanism involving an ester intermediate
We provide several lines of evidence that PC1 cleavage at the GPS domain occurs through a cis-autoproteolytic mechanism involving an ester-intermediate via N-O acyl rearrangement

Summary

Introduction

PC1 is thought to function as a cell surface signaling receptor at cell-cell/cell-matrix junctions and as a mechano-sensor in renal primary cilia that activates signaling pathways involved in renal tubular differentiation [2,3,4]. Lin et al [25] have recently described that the cleavage of EMR2, a LNB-TM7 member, occurs at its GPS domain through a similar cis-autoproteolytic mechanism.

Results

Conclusion