Molecular Cloning, Tissue Distribution, and Chromosomal Localization of Human Cationic Amino Acid Transporter 2 (HCAT2)

Hoshide, Ryuuji; Ikeda, Yukie; Karashima, Shinnyo; Matsuura, Toshinobu; Komaki, Satoru; Kishino, Tatsuya; Niikawa, Norio; Endo, Fumio; Matsuda, Ichiro

doi:10.1006/geno.1996.0613

Cited by 24 publications

(12 citation statements)

References 3 publications

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“…All genes categorized as neurotransmitter transporters and ion channels are expressed at higher levels in the old forager compared to newly emerged bee brains. These include choline transporter (Okuda et al ., 2000), glutamate transporter (Besson, et al , 1999), betaine/GABA transporter (Borden et al ., 1995), cationic amino acid transporter (Hoshide et al ., 1996), voltage-gated calcium channel subunit (Klugbauer et al ., 1999), Na + /K + -transporting ATPase α subunit (Sun et al ., 1998), and Na + -driven anion exchanger (with Na + -dependent Cl --HCO 3 exchange activity) (Romero et al ., 2000) genes. These results may suggest that the uptake of various neurotransmitters and the exchange of various ions through the plasma membrane in neurons and glia would be more enhanced in the old forager than newly emerged bee brains.…”

Section: Resultsmentioning

confidence: 99%

The Changes of Gene Expression in Honeybee (Apis mellifera) Brains Associated with Ages

Tsuchimoto

Aoki²,

Takada

et al. 2004

Zoological Science

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Honeybee (Apis mellifera) worker bees (workers) are known to perform wide variety of tasks depending on their ages. The worker's brains also show the activity and behavior-dependent chemical and structural plasticity. To test if there are any changes of gene expression associated with different ages in the worker brains, we compared the gene expression patterns between the brains of newly emerged bees and old foraging workers (foragers) by macroarray analysis. The expression of genes encoding signal transduction pathway components, ion channels, and neurotransmitter transporters is elevated in the old forager brains, suggesting that the neuronal activities would be enhanced. The mRNA levels of cell adhesion protein, transcription related factors, and plasma membrane associated proteins are also increased in the old forager brains. Meanwhile, the mRNA level of one putative cell adhesion protein is decreased in the old forager brains. These results thus suggest that the dramatic changes of gene expression occur in honeybee brains associated with ages.

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Section: Resultsmentioning

confidence: 99%

The Changes of Gene Expression in Honeybee (Apis mellifera) Brains Associated with Ages

Tsuchimoto

Aoki²,

Takada

et al. 2004

Zoological Science

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“…SNAT4 in the liver is thought to provide the major route for uptake of cationic amino acids such as arginine because this tissue does not express any of the other high-affinity cationic amino acid transporters (38). To date, evidence exists for only relatively low levels of CAT2 mRNA expression in liver, an isoform of the low-affinity cationic amino acid transporter y ϩ (20). Lack of mRNA expression for the high-affinity cationic amino acid transporter y ϩ L in human muscle and heart (48) also suggests an inverse relationship between SNAT4 and y ϩ L expression in these tissues, raising the possibility that SNAT4 may provide a route for cationic amino acid transport.…”

Section: Discussionmentioning

confidence: 99%

SNAT4 isoform of system A amino acid transporter is expressed in human placenta

Desforges¹,

Lacey²,

Glazier³

et al. 2006

American Journal of Physiology-Cell Physiology

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. SNAT4 isoform of system A amino acid transporter is expressed in human placenta. Am J Physiol Cell Physiol 290: C305-C312, 2006. First published September 7, 2005 doi:10.1152/ajpcell.00258.2005.-The system A amino acid transporter is encoded by three members of the Slc38 gene family, giving rise to three subtypes: Na ϩ -coupled neutral amino acid transporter (SNAT)1, SNAT2, and SNAT4. SNAT2 is expressed ubiquitously in mammalian tissues; SNAT1 is predominantly expressed in heart, brain, and placenta; and SNAT4 is reported to be expressed solely by the liver. In the placenta, system A has an essential role in the supply of neutral amino acids needed for fetal growth. In the present study, we examined expression and localization of SNAT1, SNAT2, and SNAT4 in human placenta during gestation. Real-time quantitative PCR was used to examine steady-state levels of system A subtype mRNA in early (6 -10 wk) and late (10 -13 wk) first-trimester and full-term (38 -40 wk) placentas. We detected mRNA for all three isoforms from early gestation onward. There were no differences in SNAT1 and SNAT2 mRNA expression with gestation. However, SNAT4 mRNA expression was significantly higher early in the first trimester compared with the full-term placenta (P Ͻ 0.01). We next investigated SNAT4 protein expression in human placenta. In contrast to the observation for gene expression, Western blot analysis revealed that SNAT4 protein expression was significantly higher at term compared with the first trimester (P Ͻ 0.05). Immunohistochemistry and Western blot analysis showed that SNAT4 is localized to the microvillous and basal plasma membranes of the syncytiotrophoblast, suggesting a role for this isoform of system A in amino acid transport across the placenta. This study therefore provides the first evidence of SNAT4 mRNA and protein expression in the human placenta, both at the first trimester and at full term. SNAT1; SNAT2; gestational expression; syncytiotrophoblast SYSTEM A IS A UBIQUITOUS Na ϩ -dependent transporter that actively transports small, zwitterionic, neutral amino acids with short, unbranched side chains such as alanine, serine, and glutamine (24). It has a unique ability to transport N-methylated amino acids such as ␣-(methylamino)isobutyric acid (MeAIB) (7). This nonmetabolized amino acid analog has been used extensively to study system A in the placenta (21,27,37).Recent data show that system A is encoded by three different members of the SLC38 gene family (Slc38a1, Slc38a2, and Slc38a4), giving rise to the three subtypes of this Na ϩ -coupled neutral amino acid transporter (SNAT): SNAT1, SNAT2, and SNAT4 (previously referred to as ATA1, ATA2, and ATA3, respectively) (31). SNAT1 was the first isoform to be cloned from rat brain and initially was designated GlnT because of its preference for glutamine as a substrate (49). Cloning of the human homolog as well as SNAT2 and SNAT4 followed (18,19,44,45,50,51). These previous studies showed the three isoforms to be highly homologous: amino acid sequences for SNAT1 and S...

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“…The aphid-Buchnera mutualism is principally based on the provision of essential amino acids from the symbiont to the host (2, 3). The high expression of the gene encoding CAT2, which is involved in the import of cationic amino acids such as lysine and arginine (essential amino acids) from the environment into the eukaryotic cells (30), is intriguing in this context. In the bacteriocyte, Buchnera cells are encased in a membrane of host origin (31,32).…”

Section: Up-regulated Genes Involved In Transportmentioning

confidence: 99%

Transcriptome analysis of the aphid bacteriocyte, the symbiotic host cell that harbors an endocellular mutualistic bacterium, Buchnera

Nakabachi

Shigenobu

Sakazume

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

210

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Aphids possess bacteriocytes, cells specifically differentiated to harbor obligatory mutualistic bacteria of the genus Buchnera, which have lost many genes that are essential for common bacterial functions. To understand the host's role in maintaining the symbiotic relationship, bacteriocytes were isolated from the pea aphid, Acyrthosiphon pisum, and the host transcriptome was investigated by using EST analysis and real-time quantitative RT-PCR. A number of genes were highly expressed specifically in the bacteriocyte, including (i) genes for amino acid metabolism, including those for biosynthesis of amino acids that Buchnera cannot produce, and those for utilization of amino acids that Buchnera can synthesize; (ii) genes related to transport, including genes for mitochondrial transporters and a gene encoding Rab, a G protein that regulates vesicular transport; and (iii) genes for putative lysozymes that degrade bacterial cell walls. Significant up-regulation of i clearly indicated that the bacteriocyte is involved in the exchange of amino acids between the host aphid and Buchnera, the key metabolic process in the symbiotic system. Conspicuously high expression of ii and iii shed light on previously unknown aspects of the host-Buchnera interactions in the symbiotic system.EST ͉ quantitative RT-PCR

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Molecular Cloning, Tissue Distribution, and Chromosomal Localization of Human Cationic Amino Acid Transporter 2 (HCAT2)

Cited by 24 publications

References 3 publications

The Changes of Gene Expression in Honeybee (Apis mellifera) Brains Associated with Ages

The Changes of Gene Expression in Honeybee (Apis mellifera) Brains Associated with Ages

SNAT4 isoform of system A amino acid transporter is expressed in human placenta

Transcriptome analysis of the aphid bacteriocyte, the symbiotic host cell that harbors an endocellular mutualistic bacterium, Buchnera

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