Disruption of clc-5 leads to a redistribution of annexin A2 and promotes calcium crystal agglomeration in collecting duct epithelial cells.
Mutations in CLCN5, which encodes the voltage-dependent Cl(-)/H(+)antiporter, CLC-5, cause Dent's disease. This disorder is characterized by low molecular-weight proteinuria, hypercalciuria, nephrocalcinosis and nephrolithiasis. Using a collecting duct cell model (mIMCD-3) in which endogenous clc-5 is disrupted by antisense clc-5 or overexpression of truncated clc-5, we demonstrate altered expression of the crystal adhesion molecule, annexin A2. Endogenously expressed annexin A2 is intracellular with limited plasma membrane localization. Following clc-5 disruption, there is both a marked increase in plasma membrane annexin A2 and an increase in cell surface crystal retention and agglomeration, which may be attenuated using pretreatment with anti-annexin A2 antibodies or wheat germ agglutinin lectin but not by concanavalin A. We hypothesize that in Dent's disease, endocytic failure leads to an accumulation at the plasma membrane of crystal-binding molecules that include annexin A2 leading to retention of calcium crystals and ultimately nephrocalcinosis and nephrolithiasis.
Carr
G
G
Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne NE2 4HH, Newcastle upon Tyne, United Kingdom.
Simmons
N L
NL
Sayer
J A
JA
D000818:Animals; D017306:Annexin A2 / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D003460:Crystallization; D004705:Endocytosis; D004847:Epithelial Cells / Q000378:metabolism; D015870:Gene Expression; D007674:Kidney Diseases / Q000378:metabolism* / Q000503:physiopathology; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D009154:Mutation; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014162:Transfection
D017306:Annexin A2; C097503:CLC-5 chloride channel; D018118:Chloride Channels; D012333:RNA, Messenger; D019158:N-Acetylneuraminic Acid; D002118:Calcium