The basolateral expression of mUT-A3 -in the mouse kidney

Facilitative UT-A urea transporters play a central role in the urinary concentrating mechanism. There are three major UT-A isoforms found in the mouse kidney: mUT-A1, mUT-A2, and mUT-A3. The major aim of this study was to identify the location and function of mUT-A3. UT-A proteins were investigated...

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Bibliographic Details
Published inAmerican journal of physiology. Renal physiology Vol. 55; no. 5; pp. F979 - F987
Main Authors STEWART, Gavin S, FENTON, Robert A, WEIDONG WANG, KWON, Tae-Hwan, WHITE, Stanley J, COLLINS, Valerie M, COOPER, Gordon, NIELSEN, Siren, SMITH, Craig P
Format Journal Article
LanguageEnglish
Published Bethesda, MD American Physiological Society 01.05.2004
Subjects
Biological and medical sciences
Fundamental and applied biological sciences. Psychology
Immunoglobulins
Kidneys
Proteins
Rodents
Urine
Vertebrates: urinary system
fluid homeostasis
Vertebrata
inner medullary collecting duct cells
Mammalia
Urinary system
Mouse
Rodentia
Homeostasis
Collecting duct
Kidney
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Summary:Facilitative UT-A urea transporters play a central role in the urinary concentrating mechanism. There are three major UT-A isoforms found in the mouse kidney: mUT-A1, mUT-A2, and mUT-A3. The major aim of this study was to identify the location and function of mUT-A3. UT-A proteins were investigated using three novel mouse UT-A-targeted antibodies: ML446, MQ2, and ML194. ML446 detected mUT-A1 and mUT-A3. ML194 detected mUT-A1 and mUT-A2. Importantly, MQ2 was found to be selective for mUT-A3. MQ2 detected a 45- to 65-kDa signal in the mouse kidney inner medulla, which was deglycosylated to a 40-kDa protein band. Immunolocalization studies showed that mUT-A3 was strongly detected in the papillary tip, mainly in the basolateral regions of inner medullary collecting duct (IMCD) cells. Immunoblotting of subcellular fractions of inner medullary protein suggested that in mouse kidney mUT-A3 was present in plasma membranes. Consistent with this, immunoelectron microscopy demonstrated that mUT-A3 was predominantly localized at the basal plasma membrane domains of the IMCD cells in mouse kidney. Heterologous expression of mUT-A3-enhanced green fluorescent protein in Madin-Darby canine kidney cells showed that the protein localized to the basolateral membrane. In conclusion, our study indicates that mUT-A3 is a basolateral membrane transporter expressed in IMCD cells. [PUBLICATION ABSTRACT]
ISSN:1931-857X
1522-1466