WordNet

write by means of a keyboard with types; "type the acceptance letter, please" (同)typewrite
a small metal block bearing a raised character on one end; produces a printed character when inked and pressed on paper; "he dropped a case of type, so they made him pick them up"
(biology) the taxonomic group whose characteristics are used to define the next higher taxon
a subdivision of a particular kind of thing; "what type of sculpture do you prefer?"
all of the tokens of the same symbol; "the word `element contains five different types of character"
printed characters; "small type is hard to read"
identify as belonging to a certain type; "Such people can practically be typed" (同)typecast
move something or somebody around; usually over long distances
an exchange of molecules (and their kinetic energy and momentum) across the boundary between adjacent layers of a fluid or across cell membranes
move while supporting, either in a vehicle or in ones hands or on ones body; "You must carry your camping gear"; "carry the suitcases to the car"; "This train is carrying nuclear waste"; "These pipes carry waste water into the river" (同)carry
transport commercially (同)send, ship
a long truck for carrying motor vehicles (同)car transporter
a crane for moving material with dispatch as in loading and unloading ships
a monosaccharide sugar that has several forms; an important source of physiological energy
writing done with a typewriter (同)typewriting

PrepTutorEJDIC

〈C〉(…の)『型』,タイプ,類型,種類(kind)《+of+名》 / 〈C〉(その種類の特質を最もよく表している)『典型』,手本,模範《+of+名》 / 〈U〉《集合的に》活字;〈C〉(1個の)活字 / 〈U〉(印刷された)字体,活字 / 〈C〉(貨幣・メダルなどの)模様,図柄 / 〈C〉血液型(blood group) / …‘を'タイプに打つ / (…として)…‘を'分類する《+名+as+名(doing)》 / …‘の'型を決める / タイプライターを打つ
(ある場所からある場所へ)…‘を'『輸送する』,運搬する《+名+from+名+to+名》 / 《文》《受動態で》(…で)…‘を'夢中にする,有頂天にする《+名+with+名》 / 〈罪人〉‘を'流刑にする / 〈U〉輸送,運送,輸送(交通)機関(transportation) / 〈C〉(軍隊や軍需品を運ぶ)輸送船,輸送機
自動車運搬用大型トラック
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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/04/21 20:35:03」(JST)

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Glucose

Glucose transporters are a wide group of membrane proteins that facilitate the transport of glucose over a plasma membrane. Because glucose is a vital source of energy for all life these transporters are present in all phyla. The GLUT or SLC2A family are a protein family that is found in most mammalian cells.

Synthesis of free glucose

Most non-autotrophic cells are unable to produce free glucose because they lack expression of glucose-6-phosphatase and, thus, are involved only in glucose uptake and catabolism. Usually produced only in hepatocytes, in fasting conditions other tissues such as the intestines, muscles, brain, and kidneys are able to produce glucose following activation of gluconeogenesis.

Glucose transport in yeast

In Saccharomyces cerevisiae glucose transport takes place through facilitated diffusion.^[1] The transport proteins are mainly from the Hxt family, but many other transporters have been identified.^[2]

Name	Properties	Notes
Snf3		low-glucose sensor; repressed by glucose; low expression level; repressor of Hxt6
Rgt2		high-glucose sensor; low expression level
Hxt1	Km: 100 mM,^[3] 129 - 107 mM^[1]	low-affinity glucose transporter; induced by high glucose level
Hxt2	Km = 1.5^[1] - 10 mM^[3]	high/intermediate-affinityglucose transporter; induced by low glucose level^[3]
Hxt3	Vm = 18.5, Kd = 0.078, Km = 28.6/34.2^[1] - 60 mM^[3]	low-affinity glucose transporter^[3]
Hxt4	Vm = 12.0, Kd = 0.049, Km = 6.2^[1]	intermediate-affinity glucose transporter^[3]
Hxt5	Km = 10 mM^[4]	Moderate glucose affinity. Abundant during stationary phase, sporulation and low glucose conditions. Transcription repressed by glucose.^[4]
Hxt6	Vm = 11.4, Kd = 0.029, Km = 0.9/14,^[1] 1.5 mM^[3]	high glucose affinity^[3]
Hxt7	Vm = 11.7, Kd = 0.039, Km = 1.3, 1.9,^[1] 1.5 mM^[3]	high glucose affinity^[3]
Hxt8		low expression level^[3]
Hxt9		involved in pleiotropic drug resistance^[3]
Hxt11		involved in pleiotropic drug resistance^[3]
Gal2	Vm = 17.5, Kd = 0.043, Km = 1.5, 1.6^[1]	high galactose affinity^[3]

Glucose transport in Mammals

GLUTs are integral membrane proteins that contain 12 membrane-spanning helices with both the amino and carboxyl termini exposed on the cytoplasmic side of the plasma membrane. GLUT proteins transport glucose and related hexoses according to a model of alternate conformation,^[5]^[6]^[7] which predicts that the transporter exposes a single substrate binding site toward either the outside or the inside of the cell. Binding of glucose to one site provokes a conformational change associated with transport, and releases glucose to the other side of the membrane. The inner and outer glucose-binding sites are, it seems, located in transmembrane segments 9, 10, 11;^[8] also, the QLS motif located in the seventh transmembrane segment could be involved in the selection and affinity of transported substrate.^[9]^[10]

Types

Each glucose transporter isoform plays a specific role in glucose metabolism determined by its pattern of tissue expression, substrate specificity, transport kinetics, and regulated expression in different physiological conditions.^[11] To date, 13 members of the GLUT/SLC2 have been identified.^[12] On the basis of sequence similarities, the GLUT family has been divided into three subclasses.

Class I

Class I comprises the well-characterized glucose transporters GLUT1-GLUT4.^[13]

Name	Distribution	Notes
GLUT1	Is widely distributed in fetal tissues. In the adult, it is expressed at highest levels in erythrocytes and also in the endothelial cells of barrier tissues such as the blood–brain barrier. However, it is responsible for the low-level of basal glucose uptake required to sustain respiration in all cells.	Levels in cell membranes are increased by reduced glucose levels and decreased by increased glucose levels.
GLUT2	Is a bidirectional transporter, allowing glucose to flow in 2 directions. Is expressed by renal tubular cells, liver cells and pancreatic beta cells. It is also present in the basolateral membrane of the small intestine epithelium. Bidirectionality is required in liver cells to uptake glucose for glycolysis, and release of glucose during gluconeogenesis. In pancreatic beta cells, free flowing glucose is required so that the intracellular environment of these cells can accurately gauge the serum glucose levels. All three monosaccharides (glucose, galactose and fructose) are transported from the intestinal mucosal cell into the portal circulation by GLUT2	Is a high-frequency and low-affinity isoform. There is some evidence^{[citation needed]} that GLUT 1 and 3 are actually the functional transporters in beta cells.
GLUT3	Expressed mostly in neurons (where it is believed to be the main glucose transporter isoform), and in the placenta.	Is a high-affinity isoform, allowing it to transport even in times of low glucose concentrations.
GLUT4	Found in adipose tissues and striated muscle (skeletal muscle and cardiac muscle).	Is the insulin-regulated glucose transporter. Responsible for insulin-regulated glucose storage.

Classes II/III

Class II comprises:

GLUT5 (SLC2A5), a fructose transporter
GLUT7 - SLC2A7 - (SLC2A7), transporting glucose out of the endoplasmic reticulum ^[14]
GLUT9 - SLC2A9 - (SLC2A9)
GLUT11 (SLC2A11)

Class III comprises:

GLUT6 (SLC2A6),
GLUT8 (SLC2A8),
GLUT10 (SLC2A10),
GLUT12 (SLC2A12), and
the H+/myoinositol transporter HMIT (SLC2A13).^[15]

Most members of classes II and III have been identified recently in homology searches of EST databases and the sequence information provided by the various genome projects.

The function of these new glucose transporter isoforms is still not clearly defined at present. Several of them (GLUT6, GLUT8) are made of motifs that help retain them intracellularly and therefore prevent glucose transport. Whether mechanisms exist to promote cell-surface translocation of these transporters is not yet known, but it has clearly been established that insulin does not promote GLUT6 and GLUT8 cell-surface translocation.

Discovery of sodium-glucose cotransport

In August 1960, in Prague, Robert K. Crane presented for the first time his discovery of the sodium-glucose cotransport as the mechanism for intestinal glucose absorption.^[16] Crane's discovery of cotransport was the first ever proposal of flux coupling in biology.^[17]^[18]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h Maier A, Asano T, Volker A, Boles E, Fuhrmann G F (2002). "Characterisation of glucose transport in Saccharomyces cerevisiae with plasma membrane vesicles (countertransport) and intact cells (initial uptake) with single Hxt1, Hxt2, Hxt3, Hxt4, Hxt6, Hxt7 or Gal2 transporters". FEMS Yeast Research 2 (4): 539–550. doi:10.1111/j.1567-1364.2002.tb00121.x. PMID 12702270.
^ uniprot list of possible glucose transporters in S. cerevisiae
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Boles E, Hollenberg C P (1997). "The molecular genetics of hexose transport in yeasts". FEMS Microbiology Reviews 21 (1): 85–111. doi:10.1111/j.1574-6976.1997.tb00346.x. PMID 9299703.
^ ^a ^b Diderich J A, Schuurmans J M, Gaalen M C, Kruckeberg A L, Van Dam K (2001). "Functional analysis of the hexose transporter homologue HXT5 in Saccharomyces cerevisiae". Yeast 18 (16): 1515–1524. doi:10.1002/yea.779. PMID 11748728.
^ Oka Y, Asano T, Shibasaki Y, Lin J, Tsukuda K, Katagiri H, Akanuma Y, Takaku F (1990). "C-terminal truncated glucose transporter is locked into an inward-facing form without transport activity". Nature 345 (6275): 550–3. doi:10.1038/345550a0. PMID 2348864.
^ Hebert D, Carruthers A (1992). "Glucose transporter oligomeric structure determines transporter function. Reversible redox-dependent interconversions of tetrameric and dimeric GLUT1". J. Biol. Chem. 267 (33): 23829–38. PMID 1429721.
^ Cloherty E, Sultzman L, Zottola R, Carruthers A (1995). "Net sugar transport is a multistep process. Evidence for cytosolic sugar binding sites in erythrocytes". Biochemistry 34 (47): 15395–406. doi:10.1021/bi00047a002. PMID 7492539.
^ Hruz P, Mueckler M (2001). "Structural analysis of the GLUT1 facilitative glucose transporter (review)". Mol. Membr. Biol. 18 (3): 183–93. doi:10.1080/09687680110072140. PMID 11681785.
^ Seatter M, De la Rue S, Porter L, Gould G (1998). "QLS motif in transmembrane helix VII of the glucose transporter family interacts with the C-1 position of D-glucose and is involved in substrate selection at the exofacial binding site". Biochemistry 37 (5): 1322–6. doi:10.1021/bi972322u. PMID 9477959.
^ Hruz P, Mueckler M (1999). "Cysteine-scanning mutagenesis of transmembrane segment 7 of the GLUT1 glucose transporter". J. Biol. Chem. 274 (51): 36176–80. doi:10.1074/jbc.274.51.36176. PMID 10593902.
^ Thorens B (1996). "Glucose transporters in the regulation of intestinal, renal, and liver glucose fluxes". Am. J. Physiol. 270 (4 Pt 1): G541–53. PMID 8928783.
^ Joost H, Thorens B (2001). "The extended GLUT-family of sugar/polyol transport facilitators: nomenclature, sequence characteristics, and potential function of its novel members (review)". Mol. Membr. Biol. 18 (4): 247–56. doi:10.1080/09687680110090456. PMID 11780753.
^ Bell G, Kayano T, Buse J, Burant C, Takeda J, Lin D, Fukumoto H, Seino S (1990). "Molecular biology of mammalian glucose transporters". Diabetes Care 13 (3): 198–208. doi:10.2337/diacare.13.3.198. PMID 2407475.
^ Page 995 in: Walter F., PhD. Boron (2003). Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. p. 1300. ISBN 1-4160-2328-3.
^ Uldry M, Thorens B (2004). "The SLC2 family of facilitated hexose and polyol transporters". Pflugers Arch. 447 (5): 480–9. doi:10.1007/s00424-003-1085-0. PMID 12750891.
^ Robert K. Crane, D. Miller and I. Bihler. “The restrictions on possible mechanisms of intestinal transport of sugars”. In: Membrane Transport and Metabolism. Proceedings of a Symposium held in Prague, August 22–27, 1960. Edited by A. Kleinzeller and A. Kotyk. Czech Academy of Sciences, Prague, 1961, pp. 439-449.
^ Ernest M. Wright and Eric Turk. “The sodium glucose cotransport family SLC5”. Pflügers Arch 447, 2004, p. 510. “Crane in 1961 was the first to formulate the cotransport concept to explain active transport [7]. Specifically, he proposed that the accumulation of glucose in the intestinal epithelium across the brush border membrane was [is] coupled to downhill Na+ transport cross the brush border. This hypothesis was rapidly tested, refined, and extended [to] encompass the active transport of a diverse range of molecules and ions into virtually every cell type.”
^ Boyd, C A R. “Facts, fantasies and fun in epithelial physiology”. Experimental Physiology, Vol. 93, Issue 3, 2008, p. 304. “the insight from this time that remains in all current text books is the notion of Robert Crane published originally as an appendix to a symposium paper published in 1960 (Crane et al. 1960). The key point here was 'flux coupling', the cotransport of sodium and glucose in the apical membrane of the small intestinal epithelial cell. Half a century later this idea has turned into one of the most studied of all transporter proteins (SGLT1), the sodium–glucose cotransporter.”

External links

Glucose Transport Proteins, Facilitative at the US National Library of Medicine Medical Subject Headings (MeSH)

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 小児および思春期における2型糖尿病の疫学、症状、および診断 epidemiology presentation and diagnosis of type 2 diabetes mellitus in children and adolescents
2. 成人糖尿病患者のマネージメントにおける血糖の自己モニタリング（SMBG） blood glucose self monitoring in management of adults with diabetes mellitus
3. 1型糖尿病の病因 pathogenesis of type 1 diabetes mellitus
4. 2型糖尿病のスクリーニング screening for type 2 diabetes mellitus
5. 乳児および小児における低血糖に対するアプローチ approach to hypoglycemia in infants and children

English Journal

Cargo-selective apical exocytosis in epithelial cells is conducted by Myo5B, Slp4a, Vamp7, and Syntaxin 3.

Vogel GF1, Klee KM2, Janecke AR3, Müller T3, Hess MW4, Huber LA5.
The Journal of cell biology.J Cell Biol.2015 Nov 9;211(3):587-604. doi: 10.1083/jcb.201506112.
Mutations in the motor protein Myosin Vb (Myo5B) or the soluble NSF attachment protein receptor Syntaxin 3 (Stx3) disturb epithelial polarity and cause microvillus inclusion disease (MVID), a lethal hereditary enteropathy affecting neonates. To understand the molecular mechanism of Myo5B and Stx3 in
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The Riddle of Nonalcoholic Fatty Liver Disease: Progression From Nonalcoholic Fatty Liver to Nonalcoholic Steatohepatitis.

Sharma M1, Mitnala S2, Vishnubhotla RK3, Mukherjee R4, Reddy DN5, Rao PN6.
Journal of clinical and experimental hepatology.J Clin Exp Hepatol.2015 Jun;5(2):147-58. doi: 10.1016/j.jceh.2015.02.002. Epub 2015 Feb 16.
Nonalcoholic fatty liver (NAFL) is an emerging global epidemic which progresses to nonalcoholic steatohepatitis (NASH) and cirrhosis in a subset of subjects. Various reviews have focused on the etiology, epidemiology, pathogenesis and treatment of NAFLD. This review highlights specifically the trigg
PMID 26155043

Carbohydrate intake and nonalcoholic fatty liver disease: fructose as a weapon of mass destruction.

Basaranoglu M1, Basaranoglu G1, Bugianesi E1.
Hepatobiliary surgery and nutrition.Hepatobiliary Surg Nutr.2015 Apr;4(2):109-16. doi: 10.3978/j.issn.2304-3881.2014.11.05.
Excessive accumulation of triglycerides (TG) in liver, in the absence of significant alcohol consumption is nonalcoholic fatty liver disease (NAFLD). NAFLD is a significant risk factor for developing cirrhosis and an independent predictor of cardiovascular disease. High fructose corn syrup (HFCS)-co
PMID 26005677

Japanese Journal

イプラグリフロジンを含めた総合的治療が血糖，NASHによる肝機能障害の改善につながった2型糖尿病の1例

森博子,岡田洋右,川口真悠子,日浦政明,阿部慎太郎,柴瑛介,島尻正平,原田大,田中良哉
糖尿病 58(4), 286-292, 2015
… イプラグリフロジンは，SLGT2（selective inhibitor of sodium glucose co-transporter 2）阻害薬のひとつであり，標的細胞は腎臓でインスリンを介さずに血糖降下作用を発現する．SGLT2阻害薬は，体重減少，降圧，脂質代謝改善，内臓脂肪減少などの副次効果が報告されており，脂肪肝など脂肪蓄積病態の改善効果も期待される．今回，食事療法と運動療法およびイプラグリフロジンによる総括的治療により，減量 …
NAID 130005071195

霊芝菌糸体培養培地抽出物のラット骨格筋培養細胞における GLUT4 膜移行促進作用

神内伸也,西川祐未,岡邑香里 [他],岩田直洋,臼井達洋,岡﨑真理,松崎広和,宮野義之,飯塚博,浅野哲,日比野康英
日本補完代替医療学会誌 12(1), 19-27, 2015
目的：霊芝菌糸体培養培地抽出物 (WER) の血糖上昇抑制作用を明らかにするために，ラット骨格筋由来培養細胞（L6 細胞）を用いて，糖輸送体 4 (GLUT4) の膜移行と糖取り込み，さらに，このプロセスに関与する細胞内シグナル伝達系を検討した．方法：WER 処理後，細胞内 GLUT4 を蛍光免疫染色法およびウエスタンブロット法により，さらにグルコースの細胞内取り込み量を解析した．また，細胞内シグ …
NAID 130005063808

新規2型糖尿病治療薬イプラグリフロジンL-プロリン（スーグラ®錠）の薬理学的特性および臨床試験成績

高須俊行,高倉昭治,加来聖司
日本薬理学雑誌 145(1), 36-42, 2015
… イプラグリフロジンL-プロリン（以下イプラグリフロジン，商品名：スーグラ®錠）は，選択的sodium/glucose co-transporter（Na+/グルコース共輸送体：SGLT）2阻害薬として2014年1月に国内で初めて承認された新しい糖尿病治療薬である．腎近位尿細管においてグルコースの再吸収を担う糖輸送体であるSGLT2を阻害し，血液中の過剰なグルコースを尿糖として体外に排泄することによって高血糖を是正する．イ …
NAID 130004827713

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★リンクテーブル★

リンク元	「glucose transporter 5」「5型グルコース輸送体」
関連記事	「type」「transport」「transporter」「typed」「typing」

「glucose transporter 5」

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe; PDBj
PDBsum	structure summary

Sugar_tr
Identifiers
Symbol	Sugar_tr
Pfam	PF00083
Pfam clan	CL0015
InterPro	IPR005828
PROSITE	PDOC00190
TCDB	2.A.1.1
OPM superfamily	15
OPM protein	4gc0
Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe; PDBj
PDBsum	structure summary