Mutational and kinetic analysis of basic amino acid transport in the cyanobacterium Synechocystis sp. PCC 6803

1990 ◽  
Vol 154 (6) ◽  
Author(s):  
Enrique Flores ◽  
AliciaM. Muro-Pastor
Keyword(s):  
Amino Acid ◽  
Kinetic Analysis ◽  
Amino Acid Transport ◽  
Basic Amino Acid ◽  
Acid Transport ◽  
Synechocystis Sp ◽  
Pcc 6803

Basic amino acid transport in renal papilla: microinfusion of Henle's loops and vasa recta

1993 ◽  
Vol 265 (6) ◽  
pp. F830-F838 ◽  
Author(s):  
W. H. Dantzler ◽  
S. Silbernagl
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Basic Amino Acid ◽  
Renal Papilla ◽  
Tubular Structures ◽  
Acid Transport ◽  
Basic Amino Acids ◽  
Neutral Amino Acids ◽  
Vasa Recta

To determine whether basic amino acids, like acidic and neutral amino acids, could be reabsorbed distal to tips of Henle's loops and recycled between loops and vasa recta in the renal papilla, we continuously microinfused ascending Henle's loops and vasa recta with 14C-labeled L-lysine (L-Lys; 1.28 mM) or L-arginine (L-Arg; 1.17 mM) and 3H-labeled inulin. We also determined percent of recovered radiolabel as intact amino acid. Like acidic and neutral amino acids, relative to inulin, approximately 30% of L-Lys and approximately 45% of L-Arg microinfused into Henle's loops were reabsorbed. However, whereas radiolabeled L-Lys reabsorption, like reabsorption of acidic and neutral amino acids, was not readily inhibited, radiolabeled L-Arg reabsorption was reduced to approximately 25% by addition of unlabled L-Arg (50 mM) or L-homoarginine (L-Homo-Arg) (50 mM) to infusate. This observation provides greater evidence for specific, carrier-mediated reabsorption for L-Arg than for acidic or neutral amino acids. About 36% (relative to inulin) of each of these amino acids microinfused into ascending vasa recta apparently was transferred directly into ipsilateral tubular structures (probably thin descending limbs of Henle's loops). Transfer of radiolabeled L-Arg was reduced to approximately 8% by the inclusion of unlabeled L-Arg (50 mM) in infusate. Transfer of unlabeled L-Lys was unaffected by inclusion of unlabeled L-Lys (50 mM) in infusate but was reduced to approximately 20% by inclusion of unlabeled L-Arg (50 mM) or L-Homo-Arg (50 mM) in infusate. (ABSTRACT TRUNCATED AT 250 WORDS)

Vba2p, A Vacuolar Membrane Protein Involved in Basic Amino Acid Transport in Schizosaccharomyces pombe

2010 ◽  
Vol 74 (10) ◽  
pp. 2166-2169 ◽  
Author(s):  
Naoko SUGIMOTO ◽  
Tomoko IWAKI ◽  
Soracom CHARDWIRIYAPREECHA ◽  
Masamitsu SHIMAZU ◽  
Takayuki SEKITO ◽  
...  
Keyword(s):  
Amino Acid ◽  
Membrane Protein ◽  
Schizosaccharomyces Pombe ◽  
Amino Acid Transport ◽  
Basic Amino Acid ◽  
Vacuolar Membrane ◽  
Acid Transport

scholarly journals Interactions between the thiol-group reagent N-ethylmaleimide and neutral and basic amino acid transporter-related amino acid transport

1999 ◽  
Vol 343 (1) ◽  
pp. 169-176 ◽  
Author(s):  
George J. PETER ◽  
Anthony DAVIES ◽  
Peter W. WATT ◽  
Jacqueline BIRRELL ◽  
Peter M. TAYLOR
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Basic Amino Acid ◽  
Thiol Group ◽  
Neutral Amino Acid ◽  
Acid Transport ◽  
Transport Activity ◽  
Direct Role ◽  
Cationic Amino Acid

The neutral and basic amino acid transport protein (NBAT) expressed in renal and jejunal brush-border membranes is involved in amino acid and cystine absorption. NBAT mutations result in Type 1 cystinuria. A C-terminal myc-tagged NBAT (NBATmyc) retains the amino acid transport and protein-protein interaction properties of NBAT when expressed in Xenopusoocytes. Neutral amino acid (Ala, Phe)-cationic amino acid (Arg) heteroexchanges related to NBATmyc expression in oocytes are inactivated by treatment with the thiol-group reagent N-ethylmaleimide (NEM), although significant Arg-Arg and Ala-Ala homoexchanges persist. Inactivation of heteroexchange activity by NEM is accompanied by loss of > 85% of alanine and cystine uptake, with smaller (< 50%) inhibition of arginine and phenylalanine uptake. NEM-sensitive cystine uptake and arginine-alanine heteroexchange (system b0,+ activity) are not expressed by an NBAT truncation mutant (NBATmyc-Sph1) lacking the 13 C-terminal amino acid residues, but the mutant expresses NEM-resistant transport activity (system y+L-like) equivalent to that of full-length NBATmyc. The deleted region of NBATmyc-Sph1 contains two cysteine residues (671/683) which may be the targets of NEM action. The synthetic amino acid 2-trifluoromethylhistidine (TFMH) stimulated alanine efflux at pH 7.5 and arginine at pH 5.5, but not vice versa, establishing the existence of distinct pathways for cationic and neutral amino acid homoexchange (TFMH is zwitterionic at pH 7.5 and cationic at pH 5.5). We suggest that NBAT expresses a combination of system b0,+ and y+L-like activities, possibly by interacting with different light-chain subunits endogenous to oocytes (as does the homologous 4F2hc protein). The C-terminus of NBAT may also have an additional, direct role in the mechanism of System b0,+ transport (the major transport activity that is defective in Type 1 cystinuria).

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