Search results for "Amino acid transporter"
showing 10 items of 45 documents
Protein Kinase C-dependent Ubiquitination and Clathrin-mediated Endocytosis of the Cationic Amino Acid Transporter CAT-1*
2011
Cationic amino acid transporter 1 (CAT-1) is responsible for the bulk of the uptake of cationic amino acids in most mammalian cells. Activation of protein kinase C (PKC) leads to down-regulation of the cell surface CAT-1. To examine the mechanisms of PKC-induced down-regulation of CAT-1, a functional mutant of CAT-1 (CAT-1-HA-GFP) was generated in which a hemagglutinin antigen (HA) epitope tag was introduced into the second extracellular loop and GFP was attached to the carboxyl terminus. CAT-1-HA-GFP was stably expressed in porcine aorthic endothelial and human epithelial kidney (HEK) 293 cells. Using the HA antibody internalization assay we have demonstrated that PKC-dependent endocytosis…
Expression of solute carrier 7A4 (SLC7A4) in the plasma membrane is not sufficient to mediate amino acid transport activity.
2002
Member 4 of human solute carrier family 7 (SLC7A4) exhibits significant sequence homology with the SLC7 subfamily of human cationic amino acid transporters (hCATs) [Sperandeo, Borsani, Incerti, Zollo, Rossi, Zuffardi, Castaldo, Taglialatela, Andria and Sebastio (1998) Genomics 49, 230–236]. It is therefore often referred to as hCAT-4 even though no convincing transport activity has been shown for this protein. We expressed SLC7A4 in Xenopus laevis oocytes, but could not detect any transport activity for cationic, neutral or anionic amino acids or for the polyamine putrescine. In addition, human glioblastoma cells stably overexpressing a fusion protein between SLC7A4 and the enhanced green f…
Activation of classical protein kinase C reduces the expression of human cationic amino acid transporter 3 (hCAT-3) in the plasma membrane
2005
We have previously shown that activation of PKC (protein kinase C) results in internalization of hCAT-1 [human CAT-1 (cationic amino acid transporter 1)] and a decrease in arginine transport [Rotmann, Strand, Martiné and Closs (2004) J. Biol. Chem. 279, 54185–54192]. However, others found increased transport rates for arginine in response to PKC activation, suggesting a differential effect of PKC on different CAT isoforms. Therefore we investigated the effect of PKC on hCAT-3, an isoform expressed in thymus, brain, ovary, uterus and mammary gland. In Xenopus laevis oocytes and human U373MG glioblastoma cells, hCAT-3-mediated L-arginine transport was significantly reduced upon treatment with…
Analysis of two not yet described member of the SLC7 family of amino acid antiporters in Drosophila melanogaster
2015
Analysis of two not yet described member of the SLC7 family of amino acid antiporters in Drosophila melanogaster. 16. rencontre du Club de neurobiologie des invertébrés
Amino acid transporter heavy chain CD98hc: Expression and role in Drosophila olfactory perception
2015
Amino acid transporter heavy chain CD98hc: Expression and role in Drosophila olfactory perception. 16. rencontre du Club de neurobiologie des invertébrés
Direct sensing of leucine by insulin-producing neurons
2015
Direct sensing of leucine by insulin-producing neurons. MoucheRhône
CATs, a family of three distinct mammalian cationic amino acid transporters
1996
Three related mammalian carrier proteins that mediate the transport of cationic amino acids through the plasma membrane have been identified in murine and human cells (CAT for cationic amino acid transporter). Models of the CAT proteins in the membrane suggest they have 12 or 14 transmembrane domains connected by short hydrophilic loops and intracellular N- and C-termini. The transport activity of the CAT proteins is sensitive to trans-stimulation and independent of the presence of sodium ions. These features agree with the behaviour of carrier proteins mediating facilitated diffusion. The three CAT proteins, CAT-1, CAT-2A and CAT-2(B) are encoded by two different genes (CAT-1 and CAT-2). C…
Expression, regulation and function of carrier proteins for cationic amino acids.
2001
Different carrier proteins exhibiting distinct transport properties participate in cationic amino acid transport. There are sodium-independent systems, such as b+, y+, y+L and b0,+, and a sodium-dependent system B0,+, most of which have now been identified at the molecular level. In most non-epithelial cells, members of the cationic amino acid transporter (CAT) family mediating system y+ activity seem to be the major entry pathway for cationic amino acids. CAT proteins underlie complex regulation at the transcriptional, post-transcriptional and activity levels. Recent evidence indicates that individual CAT isoforms are necessary for providing the substrate for nitric oxide synthesis, for ex…
Cationic Amino Acid Transporters (CATs)
2002
When the transport properties of mCAT-1 were described in 1991, the y+ carrier and major transporter for cationic amino acids seemed to be discovered. Today, we know that there are at least three different CAT isoforms that mediate y+ activity and the family might be growing. In addition, transport systems for cationic amino acids other than y + have been described and proteins that induce the respective transport activities have been identified. Consequently, the transport of cationic amino acids appears to be a complex process involving many proteins— carriers and possibly also regulatory proteins—whose expression is cell-specific and dependent on a variety of external stimuli. The multit…
REGULATION OF CATIONIC AMINO ACID TRANSPORT: The Story of the CAT-1 Transporter
2004
▪ Abstract The discovery of the function of the receptor for the ecotropic retrovirus as a membrane transporter for the essential amino acids lysine and arginine was a landmark finding in the field of molecular nutrition. This finding indicated that cationic amino acid transporters (CATs) act pathologically as viral receptors. The importance of this transporter was further supported by knockout mice that were not viable after birth. CAT-1 was the first amino acid transporter to be cloned; several other CATs were later characterized biochemically and molecularly. These transporters mediate the bidirectional transport of cationic amino acids, thus supporting important metabolic functions, s…