Localization of the urea transporter UT-B protein in human and rat erythrocytes and tissues

• Published in: American Journal of Physiology: Cell Physiology 2001-10, Vol.281 (4), p.C1318-C1325
• Main Authors: Timmer, Richard T, Klein, Janet D, Bagnasco, Serena M, Doran, John J, Verlander, Jill W, Gunn, Robert B, Sands, Jeff M
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antibodies; Aorta - chemistry; Brain Chemistry; Carrier Proteins - analysis; Carrier Proteins - genetics; Carrier Proteins - immunology; Colon - chemistry; Electrophoresis, Polyacrylamide Gel; Endothelium, Vascular - chemistry; Erythrocytes - chemistry; Gene Expression - physiology; Humans; Kidney - chemistry; Lung - chemistry; Male; Membrane Glycoproteins - analysis; Membrane Glycoproteins - genetics; Membrane Glycoproteins - immunology; Membrane Transport Proteins; Molecular Sequence Data; Myocardium - chemistry; Rats; Rats, Sprague-Dawley; RNA, Messenger - analysis; Specific Pathogen-Free Organisms; Testis - chemistry; Urea Transporters
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.2001.281.4.C1318

Departments of 1  Physiology, 2  Medicine (Renal Division), and 3  Pathology, Emory University School of Medicine, Atlanta, Georgia 30322; and 4  Department of Medicine, College of Medicine Electron Microscopy Core Facility, University of Florida College of Medicine, Gainesville, Florida 32610 A new polyclonal antibody to the human erythrocyte urea transporter UT-B detects a broad band between 45 and 65 kDa in human erythrocytes and between 37 and 51 kDa in rat erythrocytes. In human erythrocytes, the UT-B protein is the Kidd (Jk) antigen, and Jk(a+b+) erythrocytes express the 45- to 65-kDa band. However, in Jk null erythrocytes [Jk(a b )], only a faint band at 55 kDa is detected. In kidney medulla, a broad band between 41 and 54   kDa, as well as a larger band at 98 kDa, is detected. Human and rat kidney show UT-B staining in nonfenestrated endothelial cells in descending vasa recta. UT-B protein and mRNA are detected in rat brain, colon, heart, liver, lung, and testis. When kidney medulla or liver proteins are analyzed with the use of a native gel, only a single protein band is detected. UT-B protein is detected in cultured bovine endothelial cells. We conclude that UT-B protein is expressed in more rat tissues than previously reported, as well as in erythrocytes. kidney; brain; liver; testis; lung; heart; colon; Kidd antigen; endothelial cells * R. T. Timmer and J. D. Klein contributed equally to this work.