3.A.1.105.5
AbcG homologue, Snustorr, sioform A, Snu, of 808 aas and 6 TMSs in a 1 + 5 TMS arrangement at the C-terminal part of the protein. The N-terminal domain is the ATPase domain. The protein therefore has a C-M domain arrangement. Lipids in extracellular matrices (ECM) contribute to barrier function
and stability of epithelial tissues such as the pulmonary alveoli and
the skin. In insects, skin waterproofness depends on the outermost layer
of the extracellular cuticle envelope that contains cuticulin,
an unidentified water-repellent complex molecule composed of proteins,
lipids and catecholamines. Based on live-imaging analyses of fruit fly
larvae, Zuber et al. 2018 found that initially, envelope units are assembled within
putative vesicles harbouring the ABC transporter Snu and the
extracellular protein Snsl. In a second step, the content of these
vesicles is distributed to cuticular lipid-transporting nanotubes named
pore canals and to the cuticle surface, dependent on Snu function. The surface of snu and snsl mutant larvae is depleted of
lipids and cuticulin. Consequently, these animals suffer uncontrolled
water loss and penetration of xenobiotics. The data allude to a
two-step model of envelope (i.e. barrier) formation. The proposed
mechanism in principle parallels the events occurring during
differentiation of the lipid-based ECM by keratinocytes in the
vertebrate skin, suggesting establishment of analogous mechanisms of skin
barrier formation in vertebrates and invertebrates (Zuber et al. 2018).
|
Accession Number: | Q9VAU1 |
Protein Name: | Snustorr, isoform A |
Length: | 808 |
Molecular Weight: | 89334.00 |
Species: | Drosophila melanogaster (Fruit fly) [7227] |
Number of TMSs: | 7 |
Location1 / Topology2 / Orientation3: |
Membrane1 / Multi-pass membrane protein2 |
Substrate |
lipid |
---|
1: MAPKKEATLS QQQTQQPIMD LERIKRHFSW SDPSAIISTD SAMAATNNDG GTQPNAVAAW
61: GAPANGPRNT QAAVSVRHAF KAYGKKKNAN QVLNNLNMTV PKGTIYGLLG ASGCGKTTLL
121: SCIVGRRYMD AGEIFVLGGK PGTRGSGVPG KRVGYMPQEI ALYGEFSIQE TMMYFGWIFG
181: MDTKEILERL QFLLNFLDLP SEKRLVKNLS GGQQRRVSFA VALMHDPELL ILDEPTVGVD
241: PLLRQSIWNH LVHITKAGQK TVIITTHYIE EARQAHTIGL MRSGHLLAEE SPSVLLSIYK
301: CISLEEVFLK LSRIQSQKGD VTHVNFSNNI SLHAMAFGSK MDKPSSSQEG GVVGLNFHQS
361: KEVLINDSNG SIYTLNQEPY SPPPSRRNNN PNDEESCQDC YSNLCKITSK GKIRALLTKN
421: MLRMWRNVGV MLFIFALPVM QVILFCLAIG RDPQGLNLAI VNGEMNDTVR ENCYWEDGCH
481: FKNLGCRYLS HLNTSVVKTY YEDLDDAKEA VRKGTAWGAV YISENFTDAF IARANLGRDS
541: DDETIDSSEV KVWLDMSNQQ IGVMLNRDIQ LAFRDFAMGL LGQCGSNPKL GDVPIQFRDP
601: IYGTMNPSFT DFVAPGVILT IVFFLAVALT SSALIIERTE GLLDRSWVAG VSPFEILFSH
661: VITQFVVMCG QTTLVLIFML VVFGVTNNGD LFWVIVLTLL QGMCGMCFGF LISSVCELER
721: NAIQLALGSF YPTLLLSGVI WPIEGMPVVL RYISLCLPLT LATSSLRSIL TRGWAILESD
781: VYIGYVSTLS WIVGFLVLTL LVLRAKRG