title: Molecular basis for the interaction of the mammalian amino acid transporters B0AT1 and B0AT3 with their ancillary protein collectrin.
abstract: Many solute carrier 6 (SLC6) family transporters require ancillary subunits to modify their expression and activity. The main apical membrane neutral amino acid transporters in mouse intestine and kidney, B(0)AT1 and B(0)AT3, require the ancillary protein collectrin or ACE2 for plasma membrane expression. Expression and activity of SLC6 neurotransmitter transporters are modulated by interaction with syntaxin 1A. Utilizing monocarboxylate-B(0)AT1/3 fusion constructs, we discovered that collectrin is also necessary for B(0)AT1 and B(0)AT3 catalytic function. Syntaxin 1A and syntaxin 3 inhibit the membrane expression of B(0)AT1 by competing with collectrin for access. A mutagenesis screening approach identified residues on trans-membrane domains 1α, 5, and 7 on one face of B(0)AT3 as a key region involved in interaction with collectrin. Mutant analysis established residues that were involved in collectrin-dependent functions as follows: plasma membrane expression of B(0)AT3, catalytic activation, or both. These results identify a potential binding site for collectrin and other SLC6 ancillary proteins.
authors.affiliation: From the Research School of Biology and.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Fairweather
authors.affiliation: From the Research School of Biology and.
authors.forename: Angelika
authors.initials: A
authors.lastname: Bröer
authors.affiliation: Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia and.
authors.forename: Nandhitha
authors.initials: N
authors.lastname: Subramanian
authors.affiliation: From the Research School of Biology and.
authors.forename: Emrah
authors.initials: E
authors.lastname: Tumer
authors.affiliation: From the Research School of Biology and.
authors.forename: Qi
authors.initials: Q
authors.lastname: Cheng
authors.affiliation: the Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt am Main 65926, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Schmoll
authors.affiliation: Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia and.
authors.forename: Megan L
authors.initials: ML
authors.lastname: O'Mara
authors.affiliation: From the Research School of Biology and stefan.broeer@anu.edu.au.
authors.forename: Stefan
authors.initials: S
authors.lastname: Bröer
mesh_terms: D026905:Amino Acid Transport Systems / Q000235:genetics* / Q000378:metabolism; D026921:Amino Acid Transport Systems, Neutral / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D019921:Biotinylation; D016466:CHO Cells; D002384:Catalysis; D006224:Cricetinae; D003412:Cricetulus; D004331:Drosophila melanogaster; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D016296:Mutagenesis; D050480:Plasma Membrane Neurotransmitter Transport Proteins / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D050765:Qa-SNARE Proteins / Q000378:metabolism; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013379:Substrate Specificity; D050827:Syntaxin 1 / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D008562:Membrane Glycoproteins; D050480:Plasma Membrane Neurotransmitter Transport Proteins; D050765:Qa-SNARE Proteins; D011993:Recombinant Fusion Proteins; C505021:SLC6A19 protein, mouse; D050827:Syntaxin 1; C504407:Tmem27 protein, mouse; C118018:Xtrp2 protein, mouse
keywords: angiotensin-converting enzyme 2 (ACE2); broad neutral amino acid transporters; collectrin; intestinal epithelium; kidney; membrane transport; protein complex; protein-protein interaction; syntaxin 1A; syntaxin 3