Robert Andrew Fenton

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Aquaporin-9 (AQP9) is an aquaglyceroporin membrane channel shown biophysically to conduct water, glycerol, and other small solutes. Because the physiological role/s of AQP9 remain undefined and the expression sites of AQP9 remain incomplete and conflicting, we generated AQP9 knockout mice. In the absence of physiological stress, knockout mice did not(More)
The discovery of aquaporin water channels by Agre and coworkers answered a long-standing biophysical question of how the majority of water crosses biological membranes. The identification and study of aquaporins have provided insight, at the molecular level, into the fundamental physiology of water balance regulation and the pathophysiology of water balance(More)
Urea movement across plasma membranes is modulated by specialized transporter proteins that are products of two genes, termed UT-A and UT-B. These proteins play key roles in the urinary concentrating mechanism and fluid homeostasis. We have isolated and characterized a 1.4-kb cDNA from testes encoding a new isoform (UT-A5) belonging to the UT-A transporter(More)
Specialized transporter proteins that are the products of two closely related genes, UT-A (Slc14a2) and UT-B (Slc14a1), modulate the movement of urea across cell membranes. The purpose of this study was to characterize the mouse variants of two major products of the UT-A gene, UT-A1 and UT-A2. Screening a mouse kidney inner medulla cDNA library yielded(More)
The movement of urea across plasma membranes is modulated by facilitated urea transporter proteins. These proteins are the products of two closely related genes, termed UT-A (Slc14a2) and UT-B (Slc14a1). By genomic library screening and P1 artificial chromosome "shotgun" sequencing, we have determined the structure of the mouse UT-A gene. The gene is >300(More)
The blood-seminiferous tubule barrier is responsible for maintaining the unique microenvironment conducive to spermatogenesis. A key feature of the blood-testis barrier is selective permeability to solutes and water transport, conferred by the Sertoli cells of the seminiferous tubules (SMTs). Movement of fluid into the lumen of the seminiferous tubule is(More)
Two closely related genes, UT-A (Slc14a2) and UT-B (Slc14a1), encode specialized transporter proteins that modulate the movement of urea across cell membranes. In this article, we report the characterization of a cDNA isolated from human colonic mucosa encoding a novel UT-A urea transporter, hUT-A6. The encoded protein is 235 amino acids (aa) in length,(More)
The thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) is important for renal electrolyte balance and its phosphorylation causes an increase in its transport activity and cellular localization. Here, we generated phospho-specific antibodies against two conserved N-terminal phosphorylation sites (Thr53, Thr58 and Thr53/Thr58) to assess the role of arginine(More)
Vasopressin controls water excretion through regulation of aquaporin-2 (AQP2) trafficking in renal collecting duct cells. Using mass spectrometry, we previously demonstrated four phosphorylated serines (Ser256, Ser261, Ser264, and Ser269) in the carboxyl-terminal tail of rat AQP2. Here, we used phospho-specific antibodies and protein mass spectrometry to(More)
To investigate the role of inner medullary collecting duct (IMCD) urea transporters in the renal concentrating mechanism, we deleted 3 kb of the UT-A urea transporter gene containing a single 140-bp exon (exon 10). Deletion of this segment selectively disrupted expression of the two known IMCD isoforms of UT-A, namely UT-A1 and UT-A3, producing UT-A1/3(-/-)(More)