We have identified a new human cDNA, L-amino acid transporter-2 (LAT-2), that induces a system L transport activity with 4F2hc (the heavy chain of the surface antigen 4F2, also named CD98) in oocytes. Human LAT-2 is the fourth member of the family of amino acid transporters that are subunits of 4F2hc. The amino acid transport activity induced by the co-expression of 4F2hc and LAT-2 was sodium-independent and showed broad specificity for small and large zwitterionic amino acids, as well as bulky analogs (e.g. BCH (2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid)). This transport activity was highly trans-stimulated, suggesting an exchanger mechanism of transport. Expression of tagged N-myc-LAT-2 alone in oocytes did not induce amino acid transport, and the protein had an intracellular location. Co-expression of N-myc-LAT-2 and 4F2hc gave amino acid transport induction and expression of N-myc-LAT-2 at the plasma membrane of the oocytes. These data suggest that LAT-2 is an additional member of the family of 4F2 light chain subunits, which associates with 4F2hc to express a system L transport activity with broad specificity for zwitterionic amino acids. Human LAT-2 mRNA is expressed in kidney >>> placenta > > brain, liver > spleen, skeletal muscle, heart, small intestine, and lung. Human LAT-2 gene localizes at chromosome 14q11.2-13 (13 cR or ϳ286 kb from marker D14S1349). The high expression of LAT-2 mRNA in epithelial cells of proximal tubules, the basolateral location of 4F2hc in these cells, and the amino acid transport activity of LAT-2 suggest that this transporter contributes to the renal reabsorption of neutral amino acids in the basolateral domain of epithelial proximal tubule cells.Last year, three amino acid transporter cDNAs (LAT-1, y ϩ LAT-1, and y ϩ LAT-2) 1 were identified as subunits of the heavy chain of the cell surface antigen 4F2 (4F2hc, also named CD98) (1-3). These subunits co-express amino acid transport activity with 4F2hc in oocytes (i.e. system L for LAT-1, and system y ϩ L for y ϩ LAT-1 and y ϩ LAT-2) (1-4). The role of this family of proteins in amino acid transport has recently been demonstrated by the fact that mutations in the y ϩ LAT-1 gene cause lysinuric protein intolerance, an inherited amino aciduria due to a defective renal reabsorption mechanism of dibasic amino acids (5, 6). The structural and functional similarities between 4F2hc and its homologous protein rBAT suggest that a member of this family of subunits might be the subunit of rBAT needed to fully express the amino acid transport system b o,ϩ activity (reviewed in Refs. 7 and 8). After the identification of rBAT as the Type I cystinuria gene (9), this subunit is a good candidate for non-Type I cystinuria (7). A search throughout gene data bases suggests that there may be as many as four new human members of the family of subunits of 4F2hc and rBAT.Kanai and co-workers (1) identified rat LAT-1 (also known as TA1) by co-expression cloning with 4F2hc in oocytes. The coexpressed transport activity shows clear characteristic...

Blockchain technology in agri-food value chain management: A synthesis of applications, challenges and future research directions Zhao, G

Murine bone marrow macrophages were able to recognize gold nanoparticle peptide conjugates, while peptides or nanoparticles alone were not recognized. Consequently, in the presence of conjugates, macrophage proliferation was stopped and pro-inflammatory cytokines such as TNF-alpha, IL-1beta, and IL-6, as well as nitric oxide synthase (NOS2) were induced. Furthermore, macrophage activation by gold nanoparticles conjugated to different peptides appeared to be rather independent of peptide length and polarity, but dependent on peptide pattern at the nanoparticle surface. Correspondingly, the biochemical type of response also depended on the type of conjugated peptide and could be correlated with the degree of ordering in the peptide coating. These findings help to illustrate the basic requirements involved in medical nanoparticle conjugate design to either activate the immune system or hide from it in order to reach their targets before being removed by phagocytes.

Despite the increasing use of social media sites to engage consumers, the consumer brand engagement construct is still in its infancy. This study aims to contribute to existing social media research by proposing and empirically testing a model in which social media brand involvement and social media brand communication are the main precursors and brand relationship quality is a relevant outcome of social media brand engagement. The findings show that the influence of social media brand involvement on social media brand engagement is stronger than the influence of social media brand communication. The latter is due to the co-creation of users and firms. Furthermore, interaction and attention are the most relevant components of social media brand engagement, followed by enthusiasm, identification, and absorption. Social media brand engagement is a useful tool for companies to gain competitive advantages. Thus, the findings could help firms better manage their social media tools in the context of social media communication.

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