Type 1 Sodium-Dependent Phosphate Transporter acts as a Membrane Potential-Driven Urate Exporter

Phosphorus is known as a key element associated with growth, energy, and cell signaling. In plants, phosphate transporters (PHTs) are responsible for moving and distributing phosphorus in cells and organs. PHT genes have been genome-wide identified and characterized in various plant species, however, these genes have not been widely identified based on available genomic data in Camellia sativa, which is an important oil seed plant. In the present study, we found 66 PHT genes involved in phosphate transporter/translocate in C. sativa. The recognized genes belonged to PHTs1, PHTs2, PHTs4, PHOs1, PHO1 homologs, glycerol-3-PHTs, sodium dependent PHTs, inorganic PHTs, xylulose 5-PHTs, glucose-6-phosphate translocators, and phosphoenolpyruvate translocators. Our finding revealed that PHT proteins are divers based on their physicochemical properties such as Isoelectric point (pI), molecular weight, GRAVY value, and exon-intron number(s). Besides, the expression profile of PHT genes in C. sativa based on RNA-seq data indicate that PHTs are involved in response to abiotic stresses such as cold, drought, salt, and cadmium. The tissue specific expression high expression of PHO1 genes in root tissues of C. sativa. In additions, four PHTs, including a PHT4;5 gene, a sodium dependent PHT gene, and two PHO1 homolog 3 genes were found with an upregulation in response to aforementioned studied stresses. In the current study, we found that PHO1 proteins and their homologs have high potential to post-translation modifications such as N-glycosylation and phosphorylation. Besides, different cis-acting elements associated with response to stress and phytohormone were found in the promoter region of PHT genes. Overall, our results show that PHT genes play various functions in C. Sativa and regulate Camellia responses to external and intracellular stimuli. The results can be used in future studies related to the functional genomics of C. sativa.

Download Full-text

Novel Immunogenic Epitopes in the NaPi-IIb Protein: Production of Monospecific Antibodies Using Synthetic Peptides Outlined on Isoform Specific Regions of the Type IIb Sodium-Dependent Phosphate Transporter (NaPi-IIb)

Journal of Cancer Therapy ◽

10.4236/jct.2016.72015 ◽

2016 ◽

Vol 07 (02) ◽

pp. 129-151

Author(s):

Ângela Alice Amadeu Megale ◽

Jorge Mário da Costa Ferreira Júnior ◽

Letícia Batista Azevedo Rangel ◽

Maria Del Pilar Estevez Diz ◽

Max Senna Mano ◽

...

Keyword(s):

Synthetic Peptides ◽

Protein Production ◽

Phosphate Transporter ◽

Sodium Dependent ◽

Monospecific Antibodies

Download Full-text

Nature of taurodehydrocholic acid uptake in rat hepatocytes

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1988.254.2.g269 ◽

1988 ◽

Vol 254 (2) ◽

pp. G269-G274 ◽

Cited By ~ 1

Author(s):

W. G. Hardison ◽

P. J. Lowe ◽

E. Gosink

Keyword(s):

Membrane Potential ◽

Rat Hepatocytes ◽

Competitive Inhibitor ◽

Acid Uptake ◽

Isolated Rat Hepatocytes ◽

Acid Analogue ◽

Sodium Gradient ◽

Sodium Dependent ◽

Independent Process ◽

Transport Site

We studied uptake into isolated rat hepatocytes of the bile acid analogue taurodehydrocholate (TDHC) over a concentration range of 2.5-4,000 microM. Uptake was mainly by a saturable sodium-dependent process with a Km of approximately 50 microM and a Vmax of 0.036 nmol.s-1.mg protein-1. A lesser sodium-independent process was evident but was linear in the range studied. Both processes were inhibited by incubation at 37 degrees C under nitrogen in the presence of 3 mM sodium cyanide or by incubation at 0 degrees C. A single transport site was suggested by the Eadie-Hofstee plot of TDHC uptake from 2.5 to 750 microM. TDHC was a weak competitive inhibitor of taurocholic acid (TCA) uptake (Ki = 236 microM) but was not itself taken up by the TCA transport site. TCA exhibited moderately potent mixed inhibition of TDHC uptake. Uptake of both compounds was strongly inhibited by bromosulfophthalein (BSP) and Rose Bengal, whereas 0.5 mM alanine uptake was not affected. BSP exhibited a complex pattern of inhibition of TDHC uptake: mixed partial inhibition. Degree of inhibition of both TDHC and TCA uptake did not increase as BSP concentrations were increased from 50 to 100 microM. BSP did not exert its inhibitory effects by alteration of membrane potential or sodium gradients; 50 microM BSP changed membrane potential less than 10% and sodium gradient not at all. The data indicate that despite close structural analogy between TDHC and TCA, the two compounds are taken up by different sodium-dependent mechanisms. Nonetheless, the similar qualitative and quantitative effects of BSP on their uptakes suggests the mechanisms are related.

Download Full-text