Heteromeric Amino Acid Transporters
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چکیده
• The heavy subunits (molecular mass of ~90 and ~80 kDa for rBAT and 4F2hc, respectively) are type II membrane N-glycoproteins with a single transmembrane domain, an intracellular NH2 terminus, and an extracellular COOH terminus significantly homologous to insect and bacterial glucosidases (FIGURE 1). Recently, X-ray diffraction of the extracellular domain of human 4F2hc revealed a three-dimensional structure similar to that of bacterial glucosidases {a triose phosphate isomerase (TIM) barrel
منابع مشابه
Heteromeric amino acid transporters: biochemistry, genetics, and physiology.
The heteromeric amino acid transporters (HATs) are composed of two polypeptides: a heavy subunit (HSHAT) and a light subunit (LSHAT) linked by a disulfide bridge. HSHATs are N-glycosylated type II membrane glycoproteins, whereas LSHATs are nonglycosylated polytopic membrane proteins. The HSHATs have been known since 1992, and the LSHATs have been described in the last three years. HATs represen...
متن کاملMembrane topology of system xc- light subunit reveals a re-entrant loop with substrate-restricted accessibility.
Heteromeric amino acid transporters are composed of a heavy and a light subunit linked by a disulfide bridge. 4F2hc/xCT elicits sodium-independent exchange of anionic L-cysteine and L-glutamate (system x(c)(-)). Based on the accessibility of single cysteines to 3-(N-maleimidylpropionyl)biocytin, we propose a topological model for xCT of 12 transmembrane domains with the N and C termini located ...
متن کاملDetergent-Induced Stabilization and Improved 3D Map of the Human Heteromeric Amino Acid Transporter 4F2hc-LAT2
Human heteromeric amino acid transporters (HATs) are membrane protein complexes that facilitate the transport of specific amino acids across cell membranes. Loss of function or overexpression of these transporters is implicated in several human diseases such as renal aminoacidurias and cancer. HATs are composed of two subunits, a heavy and a light subunit, that are covalently connected by a dis...
متن کاملAromatic amino acid transporter AAT-9 of Caenorhabditis elegans localizes to neurons and muscle cells.
The Caenorhabditis elegans genome encodes nine homologues of mammalian glycoprotein-associated amino acid transporters. Two of these C. elegans proteins (AAT-1 and AAT-3) have been shown to function as catalytic subunits (light chains) of heteromeric amino acid transporters. These proteins need to associate with a glycoprotein heavy chain subunit (ATG-2) to reach the cell surface in a manner si...
متن کاملTHE STRUCTURAL AND FUNCTIONAL UNITS OF HETEROMERIC AMINO ACID TRANSPORTERS The heavy subunit rBAT dictates oligomerization of the HATs
Address correspondence to: Manuel Palacín and Josep Chillarón, IRB-PCB, Barcelona Science Park, Josep Samitier 1-5, 08028, and Dpt. of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Av. Diagonal, 645, E-08028, Barcelona, Spain Tel. 34 934034617 and 34 934034700; Fax 34 934034717 ; E-mail : [email protected] and [email protected] *E. F and M. J-V. contributed e...
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تاریخ انتشار 2005