L-Arginine Transport in Disease

Author(s):  
Antonio Ribeiro ◽  
Tatiana Brunini
Keyword(s):  
Helicobacter ◽  
2003 ◽  
Vol 8 (4) ◽  
pp. 245-251 ◽  
Author(s):  
George L. Mendz ◽  
Brendan P. Burns

2007 ◽  
Vol 75 (6) ◽  
pp. 2802-2810 ◽  
Author(s):  
Nanchaya Wanasen ◽  
Carol L. MacLeod ◽  
Lesley G. Ellies ◽  
Lynn Soong

ABSTRACT Leishmania spp. are obligate intracellular parasites, requiring a suitable microenvironment for their growth within host cells. We previously reported that the growth of Leishmania amazonensis amastigotes in murine macrophages (Mφs) was enhanced in the presence of gamma interferon (IFN-γ), a Th1 cytokine normally associated with classical Mφ activation and killing of intracellular pathogens. In this study, we provided several lines of evidence suggesting that IFN-γ-mediated parasite growth enhancement was associated with l-arginine transport via mouse cationic amino acid transporter 2B (mCAT-2B). (i) mRNA expression of Slc7A2, the gene encoding for mCAT-2B, as well as l-arginine transport was increased in IFN-γ-treated Mφs. (ii) Supplementation of l-arginine in Mφ cultures increased parasite growth. (iii) Parasite growth enhancement in wild-type Mφs was inhibited in the presence of nonmetabolized l-arginine analogues. (iv) IFN-γ-mediated parasite growth was absent in Mφs derived from mCAT-2B-deficient mice. Although we detected a clear upregulation of mCAT-2B and l-arginine transport, no measurable iNOS or arginase activities were observed in IFN-γ-treated, infected Mφs. Together, these data suggest an involvement of a novel l-arginine usage independent of iNOS and arginase activities during IFN-γ-mediated parasite growth enhancement. A possible role of mCAT-2B in supplying l-arginine directly to the parasites for their proliferation is discussed.


1996 ◽  
Vol 318 (3) ◽  
pp. 915-922 ◽  
Author(s):  
George J PETER ◽  
Iain G. DAVIDSON ◽  
Aamir AHMED ◽  
Lynn McILROY ◽  
Alexander R. FORRESTER ◽  
...  

The induced uptakes of l-[3H]phenylalanine and l-[3H]arginine in oocytes injected with clonal NBAT (neutral and basic amino acid transporter) cRNA show differential inactivation by pre-treatment with N-ethylmaleimide (NEM), revealing at least two distinct transport processes. NEM-resistant arginine transport is inhibited by leucine and phenylalanine but not by alanine or valine; mutual competitive inhibition of NEM-resistant uptake of arginine and phenylalanine indicates that the two amino acids share a single transporter. NEM-senstive arginine transport is inhibited by leucine, phenylalanine, alanine and valine. At least two NEM-sensitive transporters may be expressed because we have been unable to confirm mutual competitive inhibition between arginine and phenylalanine transport. The NEM-resistant transport mechanism appears to involve distinct but overlapping binding sites for cationic and zwitterionic substrates. NBAT is known to form oligomeric protein complexes in cell membranes, and its functional roles when expressed in Xenopus oocytes may include interaction with oocyte proteins, leading to increased native amino acid transport activities; these resemble NBAT-expressed activities in terms of NEM-sensitivity and apparent substrate range (including an unusual inhibition by β-phenylalanine).


Microbiology ◽  
1996 ◽  
Vol 142 (7) ◽  
pp. 1739-1747 ◽  
Author(s):  
L. S. Caskey ◽  
J. G. Lamphear ◽  
S. K. Highlander

2005 ◽  
Vol 33 (1) ◽  
pp. 105-107 ◽  
Author(s):  
R.L. Jack ◽  
A. Dubini ◽  
T. Palmer ◽  
F. Sargent

A subset of bacterial periplasmic enzymes are transported from the cytoplasm by the twin-arginine transport apparatus. Such proteins contain distinctive N-terminal signal peptides containing a conserved SRRXFLK ‘twin-arginine’ amino acid motif and often bind complex cofactors before the transport event. It is important that assembly of complex cofactor-containing, and often multi-subunit, enzymes is complete before export. Studies of the unrelated [NiFe] hydrogenase, DMSO reductase and trimethylamine N-oxide reductase systems from Escherichia coli have enabled us to define a chaperone-mediated ‘proofreading’ mechanism involved in co-ordinating assembly and export of twin-arginine transport-dependent enzymes.


2004 ◽  
Vol 286 (5) ◽  
pp. L974-L983 ◽  
Author(s):  
Sergey I. Zharikov ◽  
Karina Y. Krotova ◽  
Leonid Belayev ◽  
Edward R. Block

Pertussis toxin (PTX) induces activation of l-arginine transport in pulmonary artery endothelial cells (PAEC). The effects of PTX on l-arginine transport appeared after 6 h of treatment and reached maximal values after treatment for 12 h. PTX-induced changes in l-arginine transport were not accompanied by changes in expression of cationic amino acid transporter (CAT)-1 protein, the main l-arginine transporter in PAEC. Unlike holotoxin, the β-oligomer-binding subunit of PTX did not affect l-arginine transport in PAEC, suggesting that Gαi ribosylation is an important step in the activation of l-arginine transport by PTX. An activator of adenylate cyclase, forskolin, and an activator of protein kinase A (PKA), Sp-cAMPS, did not affect l-arginine transport in PAEC. In addition, inhibitors of PKA or adenylate cyclase did not change the activating effect of PTX on l-arginine uptake. Long-term treatment with PTX (18 h) induced a 40% decrease in protein kinase C (PKC)-α but did not affect the activities of PKC-ϵ and PKC-ζ in PAEC. An activator of PKC-α, phorbol 12-myristate 13-acetate, abrogated the activation of l-arginine transport in PAEC treated with PTX. Incubation of PTX-treated PAEC with phorbol 12-myristate 13-acetate in combination with an inhibitor of PKC-α (Go 6976) restored the activating effects of PTX on l-arginine uptake, suggesting PTX-induced activation of l-arginine transport is mediated through downregulation of PKC-α. Measurements of nitric oxide (NO) production by PAEC revealed that long-term treatment with PTX induced twofold increases in the amount of NO in PAEC. PTX also increased l-[3H]citrulline production from extracellular l-[3H]arginine without affecting endothelial NO synthase activity. These results demonstrate that PTX increased NO production through activation of l-arginine transport in PAEC.


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