PDLIM5 links kidney anion exchanger 1 (kAE1) to ILK and is required for membrane targeting of kAE1

Sci Rep. 2017 Jan 3:7:39701. doi: 10.1038/srep39701.

Abstract

Anion exchanger 1 (AE1) mediates Cl-/HCO3- exchange in erythrocytes and kidney intercalated cells where it functions to maintain normal bodily acid-base homeostasis. AE1's C-terminal tail (AE1C) contains multiple potential membrane targeting/retention determinants, including a predicted PDZ binding motif, which are critical for its normal membrane residency. Here we identify PDLIM5 as a direct binding partner for AE1 in human kidney, via PDLIM5's PDZ domain and the PDZ binding motif in AE1C. Kidney AE1 (kAE1), PDLIM5 and integrin-linked kinase (ILK) form a multiprotein complex in which PDLIM5 provides a bridge between ILK and AE1C. Depletion of PDLIM5 resulted in significant reduction in kAE1 at the cell membrane, whereas over-expression of kAE1 was accompanied by increased PDLIM5 levels, underscoring the functional importance of PDLIM5 for proper kAE1 membrane residency, as a crucial linker between kAE1 and actin cytoskeleton-associated proteins in polarized cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Anion Exchange Protein 1, Erythrocyte / genetics
  • Anion Exchange Protein 1, Erythrocyte / metabolism*
  • Cell Membrane / metabolism*
  • Cell Polarity
  • Chlorides / metabolism
  • Cytoskeleton / metabolism*
  • HEK293 Cells
  • Homeostasis
  • Humans
  • Hydrogen-Ion Concentration
  • Kidney / metabolism*
  • LIM Domain Proteins / metabolism*
  • Multiprotein Complexes / metabolism*
  • Protein Binding
  • Protein Serine-Threonine Kinases / metabolism*
  • Protein Sorting Signals / genetics
  • Protein Transport
  • RNA, Small Interfering / genetics
  • Sodium Bicarbonate / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Anion Exchange Protein 1, Erythrocyte
  • Chlorides
  • LIM Domain Proteins
  • Multiprotein Complexes
  • PDLIM5 protein, human
  • Protein Sorting Signals
  • RNA, Small Interfering
  • Sodium Bicarbonate
  • integrin-linked kinase
  • Protein Serine-Threonine Kinases