title: "Add-on" domains of Drosophila β1,4-N-acetylgalactosaminyltransferase B in the stem region and its pilot protein.
abstract: The glycolipid specific Drosophila melanogaster β1,4-N-acetylgalactosaminyltransferase B (β4GalNAcTB) depends on a zinc finger DHHC protein family member named GalNAcTB pilot (GABPI) for activity and translocation to the Golgi. The six-membrane spanning protein actually lacks the cysteine in the cytoplasmic DHHC motif, displaying DHHS instead. Here we show that the whole conserved region around the DHHS sequence, which is essential for palmitoylation in DHHC proteins, is not required for GABPI to interact with β4GalNAcTB. In contrast, the two luminal loops between transmembrane domain 3-4 and 5-6 contain conserved amino acids, which are crucial for activity. Besides the dependence on GABPI, β4GalNAcTB requires its exceptional short stem region for activity. A few hydrophobic amino acids positioned close to the transmembrane domain are essential for the interaction with GABPI. Along with its catalytic domain, β4GalNAcTB, thus, requires an area in its own stem region and two small luminal loops of GABPI as "add-on" domains. Moreover, some inactive GABPI mutants could be rescued by fusion with β4GalNAcTB, indicating their importance in direct GABPI-β4GalNAcTB interaction.
authors: Department of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors: Benjamin
authors: B
authors: Kraft
authors: Anita
authors: A
authors: Johswich
authors: Gwenda
authors: G
authors: Kauczor
authors: Meike
authors: M
authors: Scharenberg
authors: Rita
authors: R
authors: Gerardy-Schahn
authors: Hans
authors: H
authors: Bakker
references: J Biol Chem. 2010 Dec 3;285(49):38104-14
references: 20851885
references: Glycoconj J. 2008 Feb;25(2):167-75
references: 17876704
references: J Biol Chem. 2005 Mar 18;280(11):10156-63
references: 15632165
references: Mol Biol Cell. 2008 Aug;19(8):3415-25
references: 18508921
references: J Cell Biochem. 1985;28(3):207-28
references: 4066776
references: J Biol Chem. 2002 Sep 6;277(36):32421-9
references: 12130651
references: J Cell Biol. 2006 Jul 31;174(3):369-77
references: 16864653
references: Glycobiology. 2007 May;17(5):7G-9G
references: 17283039
references: J Biol Chem. 1998 May 22;273(21):12770-8
references: 9582303
references: Biochem Biophys Res Commun. 2007 Mar 9;354(2):522-7
references: 17239818
references: Glycoconj J. 2010 Oct;27(7-9):685-95
references: 21057870
references: Mol Biol Cell. 2009 Mar;20(6):1845-54
references: 19158383
references: J Lipid Res. 2006 Jun;47(6):1118-27
references: 16582420
references: J Biol Chem. 1999 Mar 26;274(13):8779-87
references: 10085119
references: J Cell Biol. 2002 Oct 14;159(1):23-8
references: 12370247
references: Cell Mol Life Sci. 2010 Jan;67(1):29-41
references: 19727557
references: Glycobiology. 2005 Apr;15(4):335-46
references: 15563714
references: J Biol Chem. 1998 May 29;273(22):13570-7
references: 9593693
references: Mol Biol Cell. 2008 Oct;19(10):4454-68
references: 18701706
references: Comput Appl Biosci. 1994 Dec;10(6):685-6
references: 7704669
references: EMBO Rep. 2004 Nov;5(11):1053-7
references: 15520806
references: J Cell Biol. 2009 Jan 12;184(1):173-83
references: 19139268
references: J Cell Biol. 1967 Jan;32(1):55-70
references: 10976201
references: Gene. 1989 Apr 15;77(1):51-9
references: 2744487
references: J Biol Chem. 2000 Jun 2;275(22):16723-9
references: 10747952
references: Glycobiology. 2010 Oct;20(10):1311-22
references: 20574042
references: Nat Rev Mol Cell Biol. 2007 Jan;8(1):74-84
references: 17183362
references: Glycobiology. 2000 Jun;10(6):601-9
references: 10814702
references: Mol Cell Biochem. 1999 May;195(1-2):219-26
references: 10395086
references: Curr Drug Targets. 2008 Apr;9(4):292-309
references: 18393823
references: J Biol Chem. 2001 Oct 5;276(40):37665-71
references: 11485999
references: J Mol Biol. 2006 Jun 9;359(3):708-27
references: 16650853
references: Methods Mol Biol. 2006;326:33-60
references: 16780193
references: J Biol Chem. 2006 Mar 31;281(13):8613-9
references: 16434399
references: Biochem Biophys Res Commun. 2002 Mar 15;291(5):1113-8
references: 11883930
references: J Biol Chem. 2002 Oct 25;277(43):41268-73
references: 12193598