Deficiency of polycystin-2 reduces Ca2+ channel activity and cell proliferation in ADPKD lymphoblastoid cells

FASEB J. 2004 May;18(7):884-6. doi: 10.1096/fj.03-0687fje. Epub 2004 Mar 4.

Abstract

Polycystin-2 (PC2), encoded by the PKD2 gene, mutated in 10-15% of autosomal-dominant polycystic kidney disease (ADPKD) patients, is a Ca2+-permeable cation channel present in kidney epithelia and other tissues. As PC2 was found expressed in B-lymphoblastoid cells (LCLs) and Ca2+ signaling pathways are important regulators of B cell function activities, we investigated whether PC2 plays some role in B-LCLs. In LCLs, PC2 was found mainly in ER membranes but ~8 times less than in kidney HEK293 cells. The same reductions were found in PKD2 and PKD1 RNA; thus, PKD genes maintained, in LCLs, the same reciprocal proportion as they do in kidney cells. In LCLs obtained from subjects carrying PKD2 mutations (PKD2-LCLs) and showing reduced PC2 levels, intracellular Ca2+ concentrations evoked by platelet-activating factor (PAF), were significantly lower than in non-PKD-LCLs. This reduction was also found in PKD1-LCLs but without PC2 reductions. Likewise, cell proliferation, which is controlled by Ca2+, was reduced in PKD2- and PKD1-LCLs. Moreover, in LCLs with PKD2 nonsense mutations, aminoglycoside antibiotics reduced the PC2 defect by promoting readthrough of stop codons. Therefore, PC2 and PC1 are functionally expressed in LCLs, which provide a model, easily obtainable from ADPKD patients, to study PKD gene expression and function.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Substitution
  • B-Lymphocytes / metabolism*
  • Calcium / metabolism*
  • Calcium Signaling* / genetics
  • Cell Division / genetics
  • Cell Line, Transformed
  • Codon, Nonsense
  • Endoplasmic Reticulum / chemistry
  • Gentamicins / pharmacology
  • Humans
  • Ion Transport / genetics
  • Kidney / pathology
  • Membrane Proteins / deficiency*
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology
  • Mutation, Missense
  • Organ Specificity
  • Platelet Activating Factor / pharmacology
  • Point Mutation
  • Polycystic Kidney, Autosomal Dominant / genetics
  • Polycystic Kidney, Autosomal Dominant / metabolism*
  • Polycystic Kidney, Autosomal Dominant / pathology
  • Proteins / genetics
  • Proteins / physiology
  • RNA, Messenger / biosynthesis
  • Suppression, Genetic / drug effects
  • TRPP Cation Channels

Substances

  • Codon, Nonsense
  • Gentamicins
  • Membrane Proteins
  • Platelet Activating Factor
  • Proteins
  • RNA, Messenger
  • TRPP Cation Channels
  • polycystic kidney disease 1 protein
  • polycystic kidney disease 2 protein
  • isepamicin
  • Calcium