Major Facilitator Superfamily; The Major Facilitator Superfamily (MFS) is a large and diverse group of secondary transporters that includes uniporters, symporters, and antiporters. MFS proteins facilitate the transport across cytoplasmic or internal membranes of a variety of substrates including ions, sugar phosphates, drugs, neurotransmitters, nucleosides, amino acids, and peptides. They do so using the electrochemical potential of the transported substrates. Uniporters transport a single substrate, while symporters and antiporters transport two substrates in the same or in opposite directions, respectively, across membranes. MFS proteins are typically 400 to 600 amino acids in length, and the majority contain 12 transmembrane alpha helices (TMs) connected by hydrophilic loops. The N- and C-terminal halves of these proteins display weak similarity and may be the result of a gene duplication/fusion event. Based on kinetic studies and the structures of a few bacterial superfamily members, GlpT (glycerol-3-phosphate transporter), LacY (lactose permease), and EmrD (multidrug transporter), MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement. Bacterial members function primarily for nutrient uptake, and as drug-efflux pumps to confer antibiotic resistance. Some MFS proteins have medical significance in humans such as the glucose transporter Glut4, which is impaired in type II diabetes, and glucose-6-phosphate transporter (G6PT), which causes glycogen storage disease when mutated.

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gi 2026661636   1 VIEEFYNQTWVHRYGESILPTTLTTLWSLSVAIFSVGGMIGSFSVGLFVNRFGRRNSMLMMNLLA 65
Cdd:cd17431    26 VIEEFYNKTLGDRYGEPISPETLTTLWSLSVAIFSVGGMIGSFSVGLFVNRFGRRNSMLYNNLLA 90

Class 1 Glucose transporters (GLUTs) of the Major Facilitator Superfamily; GLUTs, also called Solute carrier family 2, facilitated glucose transporters (SLC2A), are a family of proteins that facilitate the transport of hexoses such as glucose and fructose. There are fourteen GLUTs found in humans; they display different substrate specificities and tissue expression. They have been categorized into three classes based on sequence similarity: Class 1 (GLUTs 1-4, 14); Class 2 (GLUTs 5, 7, 9, and 11); and Class 3 (GLUTs 6, 8, 10, 12, and HMIT). GLUTs 1-4 are well-established as glucose and/or fructose transporters in various tissues and cell types. GLUT1, also called solute carrier family 2, facilitated glucose transporter member 1 (SLC2A1), displays broad substrate specificity and can transport a wide range of pentoses and hexoses including glucose, galactose, mannose, and glucosamine. It is found in the brain, erythrocytes, and in many fetal tissues. GLUT2 (or SLC2A2) is found in the liver, islet of Langerhans, intestine, and kidney, and is the isoform that likely mediates the bidirectional transfer of glucose across the plasma membrane of hepatocytes and is responsible for uptake of glucose by beta cells. GLUT3 (or SLC2A3) is found in the brain and can mediates the uptake of glucose, 2-deoxyglucose, galactose, mannose, xylose and fucose, and dehydroascorbate. GLUT4 (or SLC2A4) is an insulin-regulated facilitative glucose transporter found in adipose tissues, and in skeletal and cardiac muscle. GLUT14 (or SLC2A14) is an orphan transporter expressed mainly in the testis. GLUT proteins are comprised of about 500 amino acid residues, possess a single N-linked oligosaccharide, and have 12 transmembrane segments. They belong to the Glucose transporter -like (GLUT-like) family of the Major Facilitator Superfamily (MFS) of membrane transport proteins. MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.

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gi 2026661636   1 VIEEFYNQTWVHRYGESILPTTLTTLWSLSVAIFSVGGMIGSFSVGLFVNRFGRRNSMLMMNLLA 65
Cdd:cd17431    26 VIEEFYNKTLGDRYGEPISPETLTTLWSLSVAIFSVGGMIGSFSVGLFVNRFGRRNSMLYNNLLA 90

Class 1 Glucose transporters (GLUTs) of the Major Facilitator Superfamily; GLUTs, also called Solute carrier family 2, facilitated glucose transporters (SLC2A), are a family of proteins that facilitate the transport of hexoses such as glucose and fructose. There are fourteen GLUTs found in humans; they display different substrate specificities and tissue expression. They have been categorized into three classes based on sequence similarity: Class 1 (GLUTs 1-4, 14); Class 2 (GLUTs 5, 7, 9, and 11); and Class 3 (GLUTs 6, 8, 10, 12, and HMIT). GLUTs 1-4 are well-established as glucose and/or fructose transporters in various tissues and cell types. GLUT1, also called solute carrier family 2, facilitated glucose transporter member 1 (SLC2A1), displays broad substrate specificity and can transport a wide range of pentoses and hexoses including glucose, galactose, mannose, and glucosamine. It is found in the brain, erythrocytes, and in many fetal tissues. GLUT2 (or SLC2A2) is found in the liver, islet of Langerhans, intestine, and kidney, and is the isoform that likely mediates the bidirectional transfer of glucose across the plasma membrane of hepatocytes and is responsible for uptake of glucose by beta cells. GLUT3 (or SLC2A3) is found in the brain and can mediates the uptake of glucose, 2-deoxyglucose, galactose, mannose, xylose and fucose, and dehydroascorbate. GLUT4 (or SLC2A4) is an insulin-regulated facilitative glucose transporter found in adipose tissues, and in skeletal and cardiac muscle. GLUT14 (or SLC2A14) is an orphan transporter expressed mainly in the testis. GLUT proteins are comprised of about 500 amino acid residues, possess a single N-linked oligosaccharide, and have 12 transmembrane segments. They belong to the Glucose transporter -like (GLUT-like) family of the Major Facilitator Superfamily (MFS) of membrane transport proteins. MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.

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gi 2026661636   1 VIEEFYNQTWVHRYGESILPTTLTTLWSLSVAIFSVGGMIGSFSVGLFVNRFGRRNSMLMMNLLA 65
Cdd:cd17431    26 VIEEFYNKTLGDRYGEPISPETLTTLWSLSVAIFSVGGMIGSFSVGLFVNRFGRRNSMLYNNLLA 90

Class 2 Glucose transporters (GLUTs) of the Major Facilitator Superfamily; GLUTs, also called Solute carrier family 2, facilitated glucose transporters (SLC2A), are a family of proteins that facilitate the transport of hexoses such as glucose and fructose. There are fourteen GLUTs found in humans; they display different substrate specificities and tissue expression. They have been categorized into three classes based on sequence similarity: Class 1 (GLUTs 1-4, 14); Class 2 (GLUTs 5, 7, 9, and 11); and Class 3 (GLUTs 6, 8, 10, 12, and HMIT). GLUT5, also called Solute carrier family 2, facilitated glucose transporter member 5 (SLC2A5), is a well-established fructose transporter found in the small intestine. GLUT7 (or SLC2A7) is a high-affinity glucose and fructose transporter expressed in the small intestine and colon. GLUT9 (or SLC2A9) transports urate and fructose, and is most strongly expressed in the basolateral membranes of proximal renal tubular cells, liver and placenta. It may play a role in urate reabsorption by proximal tubules. GLUT11 (or SLC2A11) is a facilitative glucose transporter expressed in heart and skeletal muscle. GLUT proteins are comprised of about 500 amino acid residues, possess a single N-linked oligosaccharide, and have 12 transmembrane segments. They belong to the Glucose transporter -like (GLUT-like) family of the Major Facilitator Superfamily (MFS) of membrane transport proteins. MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.

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gi 2026661636   2 IEEFYNQTWVHRYGESILPTTLTTLWSLSVAIFSVGGMIGSFSVGLFVNRFGRRNSMLMMNLLA 65
Cdd:cd17432    27 IQNFYNETWTERYGTPLEESTLTLLWSLTVSIFPLGGLFGSLLVGPLVIRLGRKGTLLLNNIFA 90

Glucose transporters (GLUTs) and other similar sugar transporters of the Major Facilitator Superfamily; This family is composed of glucose transporters (GLUTs) and other sugar transporters including fungal hexose transporters (HXT), bacterial xylose transporter (XylE), plant sugar transport proteins (STP) and polyol transporters (PLT), H(+)-myo-inositol cotransporter (HMIT), and similar proteins. GLUTs, also called Solute carrier family 2, facilitated glucose transporters (SLC2A), are a family of proteins that facilitate the transport of hexoses such as glucose and fructose. There are fourteen GLUTs found in humans; they display different substrate specificities and tissue expression. They have been categorized into three classes based on sequence similarity: Class 1 (GLUTs 1-4, 14); Class 2 (GLUTs 5, 7, 9, and 11); and Class 3 (GLUTs 6, 8, 10, 12, and HMIT). GLUT proteins are comprised of about 500 amino acid residues, possess a single N-linked oligosaccharide, and have 12 transmembrane segments. The GLUT-like family belongs to the Major Facilitator Superfamily (MFS) of membrane transport proteins, which are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.

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gi 2026661636  24 TTLWSLSVAIFSVGGMIGSFSVGLFVNRFGRRNSMLMMNLL 64
Cdd:cd17315    33 TSLQGLVVSSLLLGAAIGSLFGGPLADRFGRRKSLLIAAVL 73