Deficiency of polycystin-2 reduces Ca2+ channel activity and cell proliferation in ADPKD lymphoblastoid cells.
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.
Aguiari
Gianluca
G
Department of Biochemistry and Molecular Biology, University of Ferrara, Ferrara, Italy.
Banzi
Manuela
M
Gessi
Stefania
S
Cai
Yiqiang
Y
Zeggio
Emanuela
E
Manzati
Elisa
E
Piva
Roberta
R
Lambertini
Elisabetta
E
Ferrari
Luisa
L
Peters
Dorien J
DJ
Lanza
Francesco
F
Harris
Peter C
PC
Borea
Pier Andrea
PA
Somlo
Stefan
S
Del Senno
Laura
L
D019943:Amino Acid Substitution; D001402:B-Lymphocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D002461:Cell Line, Transformed; D018389:Codon, Nonsense; D004721:Endoplasmic Reticulum / Q000737:chemistry; D005839:Gentamicins / Q000494:pharmacology; D006801:Humans; D017136:Ion Transport / Q000235:genetics; D007668:Kidney / Q000473:pathology; D008565:Membrane Proteins / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D020125:Mutation, Missense; D009928:Organ Specificity; D010972:Platelet Activating Factor / Q000494:pharmacology; D017354:Point Mutation; D016891:Polycystic Kidney, Autosomal Dominant / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011506:Proteins / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D013489:Suppression, Genetic / Q000187:drug effects; D050396:TRPP Cation Channels
D002118:Calcium; D018389:Codon, Nonsense; D005839:Gentamicins; D008565:Membrane Proteins; D010972:Platelet Activating Factor; D011506:Proteins; D012333:RNA, Messenger; D050396:TRPP Cation Channels; C016927:isepamicin