4kfw
From Proteopedia
Structural insight into Golgi membrane stacking by GRASP65 and GRASP55
Structural highlights
FunctionGORS2_RAT Key structural protein of the Golgi apparatus (By similarity). The membrane cisternae of the Golgi apparatus adhere to each other to form stacks, which are aligned side by side to form the Golgi ribbon (By similarity). Acting in concert with GORASP1/GRASP65, is required for the formation and maintenance of the Golgi ribbon, and may be dispensable for the formation of stacks (By similarity). However, other studies suggest that GORASP2 plays a role in the assembly and membrane stacking of the Golgi cisternae, and in the process by which Golgi stacks reform after breakdown during mitosis and meiosis (PubMed:10487747, PubMed:23940043). May regulate the intracellular transport and presentation of a defined set of transmembrane proteins, such as transmembrane TGFA (By similarity). Required for normal acrosome formation during spermiogenesis and normal male fertility, probably by promoting colocalization of JAM2 and JAM3 at contact sites between germ cells and Sertoli cells (By similarity). Mediates ER stress-induced unconventional (ER/Golgi-independent) trafficking of core-glycosylated CFTR to cell membrane (By similarity).[UniProtKB:Q99JX3][UniProtKB:Q9H8Y8][1] [2] Publication Abstract from PubMedThe stacking of Golgi cisternae involves GRASP65 and GRASP55. The oligomerization of the N-terminal GRASP domain of these proteins, which consists of two tandem PDZ domains, is required to tether the Golgi membranes. However, the molecular basis for GRASP assembly is unclear. Here, we determined the crystal structures of the GRASP domain of GRASP65 and GRASP55. The structures reveal similar homotypic interactions: the GRASP domain forms a dimer in which the peptide-binding pockets of the two neighboring PDZ2 domains face each other, and the dimers are further connected by the C-terminal tail of one GRASP domain inserting into the binding pocket of the PDZ1 domain in another dimer. Biochemical analysis suggests that both types of contacts are relatively weak but are needed in combination for GRASP-mediated Golgi stacking. Our results unveil a novel mode of membrane tethering by GRASP proteins and provide insight into the mechanism of Golgi stacking. Structural insight into Golgi membrane stacking by GRASP65 and GRASP55 proteins.,Feng Y, Yu W, Li X, Lin S, Zhou Y, Hu J, Liu X J Biol Chem. 2013 Sep 27;288(39):28418-27. doi: 10.1074/jbc.M113.478024. Epub, 2013 Aug 12. PMID:23940043[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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