scholarly journals Ethephon-Induced Ethylene Enhances Protein Degradation in Source Leaves, but Its High Endogenous Level Inhibits the Development of Regenerative Organs in Brassica napus

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1993
Author(s):  
Bok-Rye Lee ◽  
Rashed Zaman ◽  
Van Hien La ◽  
Sang-Hyun Park ◽  
Tae-Hwan Kim
Keyword(s):  
Amino Acid ◽  
Brassica Napus ◽  
Protein Degradation ◽  
Amino Acid Transport ◽  
Amino Acid Transporter ◽  
Acid Transport ◽  
Nitrogen Remobilization ◽  
Ethylene Concentration ◽  
Mature Leaves ◽  
Ethylene Level

To investigate the regulatory role of ethylene in the source-sink relationship for nitrogen remobilization, short-term effects of treatment with different concentrations (0, 25, 50, and 75 ppm) of ethephon (2-chloroethylphosphonic acid, an ethylene inducing agent) for 10 days (EXP 1) and long-term effects at 20 days (Day 30) after treatment with 100 ppm for 10 days (EXP 2) on protein degradation and amino acid transport in foliar sprayed mature leaves of Brassica napus (cv. Mosa) were determined. In EXP 1, endogenous ethylene concentration gradually increased in response to the treated ethephon concentration, leading to the upregulation of senescence-associated gene 12 (SAG12) expression and downregulation of chlorophyll a/b-binding protein (CAB) expression. Further, the increase in ethylene concentration caused a reduction in protein, Rubisco, and amino acid contents in the mature leaves. However, the activity of protease and expression of amino acid transporter (AAP6), an amino acid transport gene, were not significantly affected or slightly suppressed between the treatments with 50 and 75 ppm. In EXP 2, the enhanced ethylene level reduced photosynthetic pigments, leading to an inhibition of flower development without any pod development. A significant increase in protease activity, confirmed using in-gel staining of protease, was also observed in the ethephon-treated mature leaves. Ethephon application enhanced the expression of four amino acid transporter genes (AAP1, AAP2, AAP4, and AAP6) and the phloem loading of amino acids. Significant correlations between ethylene level, induced by ethephon application, and the descriptive parameters of protein degradation and amino acid transport were revealed. These results indicated that an increase in ethylene upregulated nitrogen remobilization in the mature leaves (source), which was accompanied by an increase in proteolytic activity and amino acid transport, but had no benefit to pod (sink) development.

Evidence of Salicylic Acid-Mediated Protein Degradation and Amino Acid Transport in Mature Leaves of Brassica napus

2015 ◽  
Vol 34 (3) ◽  
pp. 684-689 ◽  
Author(s):  
Qian Zhang ◽  
Bok-Rye Lee ◽  
Sang-Hyun Park ◽  
Rashed Zaman ◽  
Dong-Won Bae ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Amino Acid ◽  
Brassica Napus ◽  
Protein Degradation ◽  
Amino Acid Transport ◽  
Acid Transport ◽  
Mature Leaves

scholarly journals Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle

2014 ◽  
Vol 116 (11) ◽  
pp. 1353-1364 ◽  
Author(s):  
P. T. Reidy ◽  
D. K. Walker ◽  
J. M. Dickinson ◽  
D. M. Gundermann ◽  
M. J. Drummond ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Whey Protein ◽  
Amino Acid Transport ◽  
Amino Acid Transporter ◽  
Acid Transport ◽  
Amino Acid Availability ◽  
Acid Transporter ◽  
Dairy Protein ◽  
Myofibrillar Protein Synthesis

Increasing amino acid availability (via infusion or ingestion) at rest or postexercise enhances amino acid transport into human skeletal muscle. It is unknown whether alterations in amino acid availability, from ingesting different dietary proteins, can enhance amino acid transport rates and amino acid transporter (AAT) mRNA expression. We hypothesized that the prolonged hyperaminoacidemia from ingesting a blend of proteins with different digestion rates postexercise would enhance amino acid transport into muscle and AAT expression compared with the ingestion of a rapidly digested protein. In a double-blind, randomized clinical trial, we studied 16 young adults at rest and after acute resistance exercise coupled with postexercise (1 h) ingestion of either a (soy-dairy) protein blend or whey protein. Phenylalanine net balance and transport rate into skeletal muscle were measured using stable isotopic methods in combination with femoral arteriovenous blood sampling and muscle biopsies obtained at rest and 3 and 5 h postexercise. Phenylalanine transport into muscle and mRNA expression of select AATs [system L amino acid transporter 1/solute-linked carrier (SLC) 7A5, CD98/SLC3A2, system A amino acid transporter 2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, cationic amino acid transporter 1/SLC7A1] increased to a similar extent in both groups ( P < 0.05). However, the ingestion of the protein blend resulted in a prolonged and positive net phenylalanine balance during postexercise recovery compared with whey protein ( P < 0.05). Postexercise myofibrillar protein synthesis increased similarly between groups. We conclude that, while both protein sources enhanced postexercise AAT expression, transport into muscle, and myofibrillar protein synthesis, postexercise ingestion of a protein blend results in a slightly prolonged net amino acid balance across the leg compared with whey protein.

scholarly journals Luminal Heterodimeric Amino Acid Transporter Defective in Cystinuria

1999 ◽  
Vol 10 (12) ◽  
pp. 4135-4147 ◽  
Author(s):  
Rahel Pfeiffer ◽  
Jan Loffing ◽  
Grégoire Rossier ◽  
Christian Bauch ◽  
Christian Meier ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Autosomal Recessive ◽  
Chromosomal Localization ◽  
Amino Acid Transporter ◽  
Type I ◽  
Acid Transport ◽  
Fusion Construct ◽  
Dibasic Amino Acid ◽  
Acid Transporter

Mutations of the glycoprotein rBAT cause cystinuria type I, an autosomal recessive failure of dibasic amino acid transport (b0,+ type) across luminal membranes of intestine and kidney cells. Here we identify the permease-like protein b0,+AT as the catalytic subunit that associates by a disulfide bond with rBAT to form a hetero-oligomeric b0,+amino acid transporter complex. We demonstrate its b0,+-type amino acid transport kinetics using a heterodimeric fusion construct and show its luminal brush border localization in kidney proximal tubule. These biochemical, transport, and localization characteristics as well as the chromosomal localization on 19q support the notion that the b0,+AT protein is the product of the gene defective in non-type I cystinuria.

scholarly journals The Arabidopsis L-Type Amino Acid Transporter 5 (LAT5/PUT5) Is Expressed in the Phloem and Alters Seed Nitrogen Content When Knocked Out

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1519
Author(s):  
Rowshon A. Begam ◽  
Jayne D’Entremont ◽  
Allen Good
Keyword(s):  
Amino Acid ◽  
Nitrogen Content ◽  
Amino Acid Transport ◽  
Amino Acid Transporter ◽  
Acid Transport ◽  
Specific Expression ◽  
Tissue Specific ◽  
Tissue Specific Expression ◽  
Wide Range ◽  
Acid Transporter

The Arabidopsis L-type Amino Acid Transporter-5 (LAT5; At3g19553) was recently studied for its role in developmental responses such as flowering and senescence, under an assumption that it is a polyamine uptake transporter (PUT5). The LATs in Arabidopsis have a wide range of substrates, including amino acids and polyamines. This report extensively studied the organ and tissue-specific expression of the LAT5/PUT5 and investigated its role in mediating amino acid transport. Organ-specific quantitative RT-PCR detected LAT5/PUT5 transcripts in all organs with a relatively higher abundance in the leaves. Tissue-specific expression analysis identified GUS activity in the phloem under the LAT5/PUT5 promoter. In silico analysis identified both amino acid transporter and antiporter domains conserved in the LAT5/PUT5 protein. The physiological role of the LAT5/PUT5 was studied through analyzing a mutant line, lat5-1, under various growth conditions. The mutant lat5-1 seedlings showed increased sensitivity to exogenous leucine in Murashige and Skoog growth medium. In soil, the lat5-1 showed reduced leaf growth and altered nitrogen content in the seeds. In planta radio-labelled leucine uptake studies showed increased accumulation of leucine in the lat5-1 plants compared to the wild type when treated in the dark prior to the isotopic feeding. These studies suggest that LAT5/PUT5 plays a role in mediating amino acid transport.

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