Characterization and Regulation of the Amino Acid Transporter SNAT2 in the Small Intestine of Piglets

PLoS One. 2015 Jun 24;10(6):e0128207. doi: 10.1371/journal.pone.0128207. eCollection 2015.

Abstract

The sodium-dependent neutral amino acid transporter 2 (SNAT2), which has dual transport/receptor functions, is well documented in eukaryotes and some mammalian systems, but has not yet been verified in piglets. The objective of this study was to investigate the characteristics and regulation of SNAT2 in the small intestine of piglets. The 1,521-bp porcine full cDNA sequence of SNAT2 (KC769999) from the small intestine of piglets was cloned. The open reading frame of cDNA encodes 506 deduced amino acid residues with a calculated molecular mass of 56.08 kDa and an isoelectric point (pI) of 7.16. Sequence alignment and phylogenetic analysis revealed that SNAT2 is highly evolutionarily conserved in mammals. SNAT2 mRNA can be detected in the duodenum, jejunum and ileum by real-time quantitative PCR. During the suckling period from days 1 to 21, the duodenum had the highest abundance of SNAT2 mRNA among the three segments of the small intestine. There was a significant decrease in the expression of SNAT2 mRNA in the duodenal and jejunal mucosa and in the expression of SNAT2 protein in the jejunal and ileal mucosa on day 1 after weaning (P < 0.05). Studies with enterocytes in vitro showed that amino acid starvation and supplementation with glutamate, arginine or leucine enhanced, while supplementation with glutamine reduced, SNAT2 mRNA expression (P < 0.05). These results regarding the characteristics and regulation of SNAT2 should help to provide some information to further clarify its roles in the absorption of amino acids and signal transduction in the porcine small intestine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Transport System A / genetics*
  • Animals
  • Carrier Proteins / biosynthesis
  • Carrier Proteins / genetics*
  • Glutamic Acid / genetics
  • Glutamic Acid / metabolism
  • Intestine, Small / metabolism*
  • Phylogeny*
  • RNA, Messenger / biosynthesis
  • Sequence Alignment
  • Swine
  • Weaning

Substances

  • Amino Acid Transport System A
  • Carrier Proteins
  • RNA, Messenger
  • SLC38A2 protein, human
  • Glutamic Acid

Grants and funding

This work was supported by the National Natural Science Foundation of China (31372326 and 31330075) and the 973 National Projects Subject (2013CB127302 and 2013CB127306).