Partitioning-Defective-6-Ephrin-B1 Interaction Is Regulated by Nephrin-Mediated Signal and Is Crucial in Maintaining Slit Diaphragm of Podocyte

Am J Pathol. 2020 Feb;190(2):333-346. doi: 10.1016/j.ajpath.2019.10.015. Epub 2019 Dec 16.

Abstract

Ephrin-B1 plays a critical role at slit diaphragm. Partitioning-defective (Par)-6 is down-regulated in podocyte of ephrin-B1 knockout mouse, suggesting that Par-6 is associated with ephrin-B1. Par polarity complex, consisting of Par-6, Par-3, and atypical protein kinase C, is essential for tight junction formation. In this study, the expression of Par-6 was analyzed in the normal and nephrotic syndrome model rats, and the molecular association of Par-6, Par-3, ephrin-B1, and nephrin was assessed with the human embryonic kidney 293 cell expression system. Par-6 was concentrated at slit diaphragm. Par 6 interacted with ephrin-B1 but not with nephrin, and Par-3 interacted with nephrin but not with ephrin-B1. The complexes of Par-6-ephrin-B1 and Par-3-nephrin were linked via extracellular sites of ephrin-B1 and nephrin. The Par-6-ephrin-B1 complex was delinked from the Par-3-nephrin complex, and Par-6 and ephrin-B1 were clearly down-regulated already at early phase of nephrotic model. The alteration of Par-6/ephrin-B1 advanced that of Par-3/nephrin. Stimulation to nephrin phosphorylated not only nephrin but also ephrin-B1, and consequently inhibited the interaction between ephrin-B1 and Par-6. Par-6 appeared at presumptive podocyte of early developmental stage and moved to basal area at capillary loop stage to participate in slit diaphragm formation at the final stage. Par-6-ephrin-B1 interaction is crucial for formation and maintenance of slit diaphragm of podocyte.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / physiology*
  • Animals
  • Animals, Newborn
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Diaphragm
  • Ephrin-B1 / genetics
  • Ephrin-B1 / metabolism*
  • HEK293 Cells
  • Humans
  • Kidney Glomerulus / cytology*
  • Kidney Glomerulus / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Knockout
  • Nephrotic Syndrome / metabolism
  • Nephrotic Syndrome / pathology*
  • Phosphorylation
  • Podocytes / cytology*
  • Podocytes / metabolism
  • Rats
  • Rats, Wistar

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Ephrin-B1
  • Membrane Proteins
  • Par6 protein, mouse
  • Pard6a protein, rat
  • nephrin