The calcium-binding EF-hand in polycystin-L is not a domain for channel activation and ensuing inactivation

FEBS Lett. 2002 Apr 10;516(1-3):270-8. doi: 10.1016/s0014-5793(02)02513-9.

Abstract

Polycystin-L (PCL) shares high homology with polycystin-2, the product of polycystic kidney disease gene-2. It was previously shown that the PCL forms a non-selective cation channel activated by calcium influx. However, it remains unclear whether calcium activates/inactivates PCL by binding to the EF-hand motif located on the cytoplasmic carboxyl-terminus. Here we obtained two PCL splice variants from liver (PCL-LV, lacking the EF-hand) and testis (PCL-TS, lacking 45 amino acids on the carboxyl tail) using PCR-based approaches. When expressed in Xenopus oocytes and studied using electrophysiology both splice variants exhibited basal cation channel activity and calcium-induced channel activation. While PCL-TS displayed similar activation to PCL, PCL-LV exhibited a three-fold increased activation. All five PCL C-terminal artificial truncation mutants also exhibited basal and calcium-activated channel activities, in particular the mutant T622X lacking the EF-hand was associated with increased activation. Our data demonstrate that the EF-hand and other parts of the carboxyl tail of PCL are not determinants of channel activation/inactivation although the EF-hand seems to be involved in the modulation of these processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Binding Sites
  • Calcium Channels
  • Cloning, Molecular
  • Female
  • Humans
  • In Vitro Techniques
  • Ion Channels / chemistry*
  • Ion Channels / genetics
  • Ion Channels / metabolism*
  • Male
  • Membrane Glycoproteins / chemistry*
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Molecular Sequence Data
  • Mutation
  • Oocytes / metabolism
  • Phosphoproteins / chemistry*
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Polycystic Kidney, Autosomal Dominant / genetics
  • Protein Structure, Tertiary
  • Receptors, Cell Surface
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sequence Deletion
  • Sequence Homology, Amino Acid
  • TRPP Cation Channels
  • Xenopus

Substances

  • Calcium Channels
  • Ion Channels
  • Membrane Glycoproteins
  • Membrane Proteins
  • PKD2L1 protein, human
  • Phosphoproteins
  • Receptors, Cell Surface
  • Recombinant Proteins
  • TRPP Cation Channels
  • polycystic kidney disease 2 protein

Associated data

  • GENBANK/AF073481
  • GENBANK/AF116458
  • GENBANK/U24497
  • GENBANK/U50928
  • RefSeq/NM_014386