Sean Munro

..Recent studies have helped to establish how cells maintain and restrict these determinants and explain how this system is exploited by invading pathogens...

..Each organelle or vesicle class is typically associated with one or more Rab, with the Rabs present in a particular cell reflecting that cell's complement of organelles and trafficking routes...

..This review will examine what is known about the function of these large coiled-coil proteins in membrane traffic...

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..These recruiting determinants are then recognized by cytosolic proteins that facilitate the formation and delivery of vesicles at the correct compartment...

..Recent work is starting to reveal the mechanisms by which these labile landmarks are generated in a spatially restricted manner on specific parts of the Golgi...

..Consideration of how these targeting domains could function has provided insights into the organization of the Golgi and its protein and lipid content...

..Genetic analysis in a number of species has shown that Arl1 is not essential for exocytosis, but rather suggest that it is required for traffic from endosomes to the Golgi...

..This review discusses the potential of the yeast system to address these issues...

..This suggests that these determinants are what specify organelle identity, and raises interesting questions about how they are generated in an organelle-specific fashion...

..It also has distant homology to bacterial glycosyltransferases, although it is not clear if this reflects a shared enzymatic activity, or merely a related structure...

..Tassin, C. Fedriani, and M. Bornens. 2004. Cell. 118:323-335). In contrast, we find that this region binds to the Golgi in a GRAB domain-dependent manner, suggesting that GMAP-210 may not link the Golgi to gamma-tubulin and centrosomes...

..This suggests that the targeting of ARFRP1/Arl3p to the Golgi is mediated by a direct interaction between its acetylated N terminus and Sys1p/hSys1...

..Thus, it appears that Dop1 plays a widespread role in membrane organization, and Mon2 acts as a scaffold to recruit the Golgi-localized pool of Dop1...

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..In addition, they indicate that the lumen of the yeast Golgi contains UDP-GlcNAc, which may facilitate reconstitution of higher eukaryotic N-glycan processing...

..Despite no conservation of sequence, topology, or even helical direction, several other effectors form similar interactions with small GTPases via a pair of alpha helices, suggesting a common structural basis for effector recognition...

..Moreover the Sec7 domain of Yel1 is required for its membrane targeting and for that of Arf3. Finally we show that the isolated Yel1 Sec7 domain strongly stimulates nucleotide exchange activity specifically on Arf3 in vitro...

..This is underestimated by examination of single mutants, providing a possible explanation for discrepancies between yeast and mammalian studies on Atg9 localization and autophagosome formation...

..Binding sites for diverse Rabs could ensure that incoming carriers are captured on first contact and moved to their correct destination within the stack...

..A splice variant of SKIP that lacks a light chain binding motif does not stimulate movement, suggesting fine-tuning by alternative splicing...

..Live cell imaging shows that lysosomes move more frequently both toward and away from the cell periphery, suggesting a role for Arl8a and Arl8b as positive regulators of lysosomal transport...

..Finally, we find that Arl3p is required in vivo for the targeting of Arl1p, explaining its requirement for the normal distribution of Imh1p...

..The Arl4 family thus defines a signal-transduction pathway that can mediate the plasma-membrane recruitment of cytohesins independently of a requirement for the generation of PtdIns(3,4,5)P(3)...

..When isolated from transfected cells the C-terminal domain of AKAP450 was associated with calmodulin, suggesting that this protein could contribute to centrosome assembly...

..Thus, the exocyst may act in both Golgi to plasma membrane traffic and endocytic cycling, and hence in oocytes is recruited to clathrin-coated pits to facilitate the rapid recycling of Yolkless...

..This divergent trafficking of HLA-F implicates an alternative function for HLA-F, independent of loading with peptides in the ER...

..The conserved histidine is necessary for Coy1p's activity in cells lacking Gos1p, suggesting that the TMD of these transmembrane Golgi coiled-coil proteins is directly involved in their function...

..GFP fusions to Osh2p and Osh3p showed intracellular distributions distinct from that of Osh1p, and their PH domains appear to contribute to their differing localizations...

..We show that in mammalian cells, Arl1 is necessary for Golgi recruitment of BIG1 and BIG2 but not GBF1. Thus, Arl1 acts to direct a trans-Golgi-specific Arf1 GEF, and hence active Arf1, to the trans side of the Golgi...

..The pervasive presence of organelle-specific features among the TMDs of a particular organelle has implications for TMD prediction, regulation of protein activity by location, and sorting of proteins and lipids in the secretory pathway...

..Finally, we show that a simple glycoprotein based on hen egg lysozyme can be used as a substrate for modification by purified M-Pol I in vitro...

..These observations are more consistent with lipid-based sorting of ST TMD, but they also allow for reconciliation with the kin recognition model which appears to act on sequences outside of the TMD...

..Here we review what is known about all the members of the Arf family, along with the known regulatory molecules that convert them between GDP- and GTP-bound states...

..Moreover, the diversity of tethering complexes in the cell suggests that not all tethering events occur through the same mechanisms...

..This result suggests that this small domain functions to recruit specific coiled-coil proteins to the Golgi by recognising a determinant that has been well conserved in eukaryotic evolution...

..Our data suggest that these two multi-protein complexes are responsible for the synthesis and initial branching of the long alpha-1,6-linked backbone of the hypermannose structure attached to many yeast glycoproteins...

..It does, however, contain a pleckstrin homology (PH) domain, which in other proteins has been found to mediate regulated membrane binding, although in all previously studied examples the binding is to the plasma membrane...

..Moreover, there is a strong synergistic effect on the maturation of proteinases A and B when both MRL1 and VPS10 are deleted, which suggests that Mrl1p may serve as a sorting receptor in the delivery of vacuolar hydrolases...

..Interestingly, Anp1p is localized to the endoplasmic reticulum (ER), implying that some function of the ER is required to maintain a functional Golgi apparatus...

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..The identification of Mnn2p and Mnn5p allows us to assign Golgi proteins to all of the catalytic steps in S. cerevisiae mannan synthesis...

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..We propose a more consistent nomenclature for the human members of the Arf family that may also serve as a guide for nomenclature in other species...

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