Ephrin-B1 localizes at the slit diaphragm of the glomerular podocyte.
Ephs and ephrins are a family of membrane-bound proteins that function as receptor-ligand pairs. Members of the Eph-ephrin-B family have recently been reported to regulate the paracellular permeability of epithelial cells. In this study, we analyzed the expression and the function of ephrin-B1 in glomeruli. Using immunofluorescence (IF), we found that ephrin-B1 was expressed along the glomerular capillary loop. Immunoelectron microscopy revealed that ephrin-B1 expression was restricted at the slit diaphragm. Dual labeled IF showed ephrin-B1 colocalized with the slit diaphragm proteins nephrin and CD2-associated protein. Ephrin-B1 colocalized with nephrin at the late capillary loop stage of kidney development. Additionally, injection of rats with a nephritogenic anti-nephrin antibody (ANA) reduced ephrin-B1 expression. When podocytes were cultured in vitro, they extruded processes that co-stained for ephrin-B1 and for CD2-associated protein. When these podocytes were treated in culture with small interfering RNA for ephrin-B1, CD2-associated protein was reduced in the processes, with a remaining faint perinuclear staining. We suggest that ephrin-B1 has a role in maintaining barrier function at the slit diaphragm.
Hashimoto
T
T
Department of Cell Biology, Institute of Nephrology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Karasawa
T
T
Saito
A
A
Miyauchi
N
N
Han
G D
GD
Hayasaka
K
K
Shimizu
F
F
Kawachi
H
H
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000009:adverse effects / Q000276:immunology / Q000494:pharmacology; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000378:metabolism; D036387:Ephrin-B1 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D036388:Ephrin-B2 / Q000032:analysis / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D007674:Kidney Diseases / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D007678:Kidney Glomerulus / Q000378:metabolism* / Q000473:pathology; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D050199:Podocytes / Q000378:metabolism* / Q000473:pathology; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D048868:Adaptor Proteins, Signal Transducing; D000888:Antibodies, Anti-Idiotypic; C114545:CD2-associated protein; D003598:Cytoskeletal Proteins; D036387:Ephrin-B1; D036388:Ephrin-B2; D008565:Membrane Proteins; D034741:RNA, Small Interfering; C113267:nephrin