Protein
Protein unc-13 homolog 4B
Organism
Drosophila melanogaster
Function
Essential for tracheal development in embryos. Functions with the GTPase Rab39 and downstream of dnd, to regulate lumen fusion between previously separate tracheal branches (anastomosis). Essential component of secretory lysosome-related organelles (SLs) that are present in the tracheal fusion tip cells (FCs). Mediates intracellular fusion of the extending tracheal stalk cell lumen in the FCs by recruiting the SNARE complex component Syx1A to the SLs, this may then enable the SLs to interact with complementary SNAREs (such as Syb) present in the apical membrane of the FC-FC interface and the membranes of the separate tracheal stalk cells. May also function in the maturation and exocytosis of the SLs.
Similarity
Belongs to the unc-13 family.
Sequence
MDEEQMWKGFFFKLQELKMNPPTEHEHQLQDGDDGFFEKFGSLLRQKSQIDEGVLKSSLAPLEENGSGGEEDSDESPDGTLQLSQDSECTSIDTFATESTLASSSDKDISTSVLDSAPVMNVTDLYEEILFEIFNNIGCENNEECTNSLVEFVQDAFKIPNATHEEIYEAARLKEPPNVRLNVEIIKAENLMSKDSNGLSDPFVTLYLESNGSHRYNSSVKPATLNPIWEEHFSLPITENARDEVLIVEVWDFDAAETVKEKVNKILDVKGVKGLSKLMKEIAVTASSGKHDNELIGRAAITLKSIPVSGLTVWYNLEKGSKGRSRGSLLVNLALSAEKNKSVAVQEHKNLLKLLLMYELETSQVANYWWSGKFSPNAELIRSQHAAQSGLTPFDCALSQWHAYSTIHETHKLNFTLFNSILDVVVPVITYMQNDSEDVKTFWDGVKRLLPSCFAVLRKLRSKNTSDKNIIRALNEVLDILKKIKELEVPESVDIFPKSVYGWLHTNDTDETCNIDTAIEDAINTGTREWLEHIVEGSRQSKNTETDDEKLQYVIKLIQMVRSDLQRAMEYFDKIFYHKIQLNYSAVLYLFYDSKLAEICKSIIIEVCNNIKRLDVPDDQFEYLPNLENVNMGTTLFEVYLILKRYVQLGESLCSEPLELSNFYPWFERGVTHWLDISIIKALSRIQKAIDLDQLKAVDETVKYSSSAVDTLSIFYQIKIFWQQLDWPEVEGSYIFVAKIVNDLCRCCIFYAQQMSRRVENIFIADDNNKNFILSEEWCIAINNMDYIRQSLPSFIKELSIDDIIKRLGEYRTNLEAERCASTIKTVIENALDTERNQIVELIEIVARKMAPPIRRYLAEGAEVLAKDSNSMDQLMMYLESSLATLYDTLNEINFQRILDGIWSELSIIMYDLIQSNLDKRRPPAFFQNLNNTLQTMMDCFKMGNLQTSDIKILSSIQSRLRLYSLETSDLIHQYYLERLENQKSQESSPYGQLTITAQLTDTGLLLNILNARNLLPMDSNGSVDSFVKASFMPTSRFNDVPTVKTNVHNKSCFPLYDQEFRINLSDHQRSEKNSLIVFSIKDKDLFGMSSQYIAESYISFADLEATPPGEQIMMNLSRPEYTDSESLRALEYRLGDKQAKDFLKKLKNRSFS