title: Role of the N-terminal transmembrane domain in the endo-lysosomal targeting and function of the human ABCB6 protein.
abstract: ATP-binding cassette, subfamily B (ABCB) 6 is a homodimeric ATP-binding cassette (ABC) transporter present in the plasma membrane and in the intracellular organelles. The intracellular localization of ABCB6 has been a matter of debate, as it has been suggested to reside in the mitochondria and the endo-lysosomal system. Using a variety of imaging modalities, including confocal microscopy and EM, we confirm the endo-lysosomal localization of ABCB6 and show that the protein is internalized from the plasma membrane through endocytosis, to be distributed to multivesicular bodies and lysosomes. In addition to the canonical nucleotide-binding domain (NBD) and transmembrane domain (TMD), ABCB6 contains a unique N-terminal TMD (TMD0), which does not show sequence homology to known proteins. We investigated the functional role of these domains through the molecular dissection of ABCB6. We find that the folding, dimerization, membrane insertion and ATP binding/hydrolysis of the core-ABCB6 complex devoid of TMD0 are preserved. However, in contrast with the full-length transporter, the core-ABCB6 construct is retained at the plasma membrane and does not appear in Rab5-positive endosomes. TMD0 is directly targeted to the lysosomes, without passage to the plasma membrane. Collectively, our results reveal that TMD0 represents an independently folding unit, which is dispensable for catalysis, but has a crucial role in the lysosomal targeting of ABCB6.
authors: *Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1117, Hungary.
authors: Katalin
authors: K
authors: Kiss
authors: *Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1117, Hungary.
authors: Nora
authors: N
authors: Kucsma
authors: *Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1117, Hungary.
authors: Anna
authors: A
authors: Brozik
authors: *Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1117, Hungary.
authors: Gabor E
authors: GE
authors: Tusnady
authors: †Institut Curie, Centre de Recherche, Paris F-75248, France Structure and Membrane Compartments CNRS UMR144, Paris F-75248, France.
authors: Ptissam
authors: P
authors: Bergam
authors: †Institut Curie, Centre de Recherche, Paris F-75248, France Structure and Membrane Compartments CNRS UMR144, Paris F-75248, France.
authors: Guillaume
authors: G
authors: van Niel
authors: *Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1117, Hungary.
authors: Gergely
authors: G
authors: Szakacs
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D019943:Amino Acid Substitution; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D019281:Dimerization; D004705:Endocytosis; D006367:HeLa Cells; D006801:Humans; D006868:Hydrolysis; D020014:K562 Cells; D008247:Lysosomes / Q000378:metabolism* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D057146:Multivesicular Bodies / Q000378:metabolism* / Q000648:ultrastructure; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017510:Protein Folding; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: C107991:ABCB6 protein, human; D018528:ATP-Binding Cassette Transporters; D050505:Mutant Proteins; D010446:Peptide Fragments; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D000255:Adenosine Triphosphate
references: Biochem Biophys Res Commun. 2001 Nov 16;288(5):1258-64
references: 11700048
references: Biochim Biophys Acta. 1999 Dec 6;1461(2):237-62
references: 10581359
references: Proc Natl Acad Sci U S A. 2002 Jul 23;99(15):9685-90
references: 12093921
references: J Biol Chem. 2000 Aug 4;275(31):23530-9
references: 10918072
references: J Gen Physiol. 2000 Sep;116(3):477-500
references: 10962022
references: Biochem Biophys Res Commun. 2000 Oct 5;276(3):1314-9
references: 11027628
references: J Cell Sci. 2000 Dec;113 Pt 24:4451-61
references: 11082039
references: Biochem J. 2001 May 15;356(Pt 1):71-5
references: 11336637
references: Genome Res. 2001 Jul;11(7):1156-66
references: 11435397
references: Biochem Biophys Res Commun. 2001 Jul 6;285(1):111-7
references: 11437380
references: J Biol Chem. 2002 Aug 23;277(34):31048-55
references: 12060660
references: Mol Biol Cell. 2002 Dec;13(12):4443-55
references: 12475964
references: Annu Rev Biochem. 2003;72:395-447
references: 12651740
references: J Biol Chem. 2004 Mar 12;279(11):10142-7
references: 14679198
references: Biophys J. 2004 Jun;86(6):3993-4003
references: 15189895
references: Biochem Biophys Res Commun. 2004 Jul 30;320(3):860-7
references: 15240127
references: J Biol Chem. 2004 Oct 1;279(40):41670-8
references: 15252017
references: Anal Biochem. 1972 Aug;48(2):422-7
references: 4115981
references: Annu Rev Cell Biol. 1989;5:483-525
references: 2557062
references: J Biol Chem. 1992 Mar 5;267(7):4854-8
references: 1347044
references: Annu Rev Cell Biol. 1992;8:67-113
references: 1282354
references: J Cell Sci. 1992 Nov;103 ( Pt 3):857-62
references: 1478975
references: Proc Natl Acad Sci U S A. 1993 Sep 15;90(18):8392-6
references: 7690960
references: J Biol Chem. 1994 Mar 25;269(12):8986-92
references: 7907596
references: J Biol Chem. 1998 Nov 27;273(48):32167-75
references: 9822694
references: J Biol Chem. 1999 Jan 29;274(5):3141-50
references: 9915853
references: J Biol Chem. 1999 Apr 30;274(18):12209-12
references: 10212185
references: Mol Cell Proteomics. 2005 Feb;4(2):133-43
references: 15579476
references: Immunol Cell Biol. 2005 Oct;83(5):475-82
references: 16174096
references: J Immunol. 2005 Oct 15;175(8):5104-14
references: 16210614
references: FEBS Lett. 2006 Feb 13;580(4):1017-22
references: 16337630
references: Nat Rev Drug Discov. 2006 Mar;5(3):219-34
references: 16518375
references: J Cell Sci. 2006 May 15;119(Pt 10):2003-14
references: 16621890
references: Dev Cell. 2006 Jun;10(6):839-50
references: 16740485
references: Physiol Rev. 2006 Oct;86(4):1179-236
references: 17015488
references: Nature. 2006 Oct 5;443(7111):586-9
references: 17006453
references: Biochemistry. 2007 Aug 21;46(33):9443-52
references: 17661442
references: J Cell Biochem. 2007 Oct 15;102(3):650-64
references: 17407154
references: Am J Physiol Cell Physiol. 2008 Feb;294(2):C579-90
references: 18160489
references: Biochem Biophys Res Commun. 2008 May 2;369(2):369-75
references: 18279659
references: Philos Trans R Soc Lond B Biol Sci. 2009 Jan 27;364(1514):239-45
references: 18957379
references: Biochim Biophys Acta. 2009 Apr;1793(4):605-14
references: 19046998
references: Histochem Cell Biol. 2010 Jan;133(1):41-55
references: 19830447
references: Traffic. 2010 Mar;11(3):383-93
references: 20377823
references: PLoS One. 2010;5(9):e12938
references: 20886084
references: J Biol Chem. 2011 Mar 11;286(10):8481-92
references: 21199866
references: EMBO J. 2011 Aug 31;30(17):3481-500
references: 21878991
references: Dev Cell. 2011 Oct 18;21(4):708-21
references: 21962903
references: Am J Hum Genet. 2012 Jan 13;90(1):40-8
references: 22226084
references: Nat Genet. 2012 Feb;44(2):170-3
references: 22246506
references: J Biol Chem. 2012 Apr 13;287(16):12679-90
references: 22294697
references: PLoS One. 2012;7(5):e37378
references: 22655043
references: Am J Hematol. 2013 Jan;88(1):66-72
references: 23180570
references: Vox Sang. 2013 Feb;104(2):159-65
references: 22958180
references: J Biol Chem. 2013 Aug 2;288(31):22658-69
references: 23792964
references: J Invest Dermatol. 2013 Sep;133(9):2221-8
references: 23519333
references: Cold Spring Harb Perspect Biol. 2013 Nov;5(11):a016790
references: 24186068
references: PLoS One. 2013;8(11):e79808
references: 24224009
references: PLoS One. 2014;9(2):e87250
references: 24498303
references: PLoS One. 2014;9(10):e111590
references: 25360778
references: Biochim Biophys Acta. 2002 Mar 19;1574(2):117-30
references: 11955620