6j7f
From Proteopedia
Complex of GGTaseIII, farnesyl-Ykt6 (C-terminal methylated), and GGPP
Structural highlights
FunctionPGTB2_HUMAN Catalyzes the transfer of a geranylgeranyl moiety from geranylgeranyl diphosphate to both cysteines of Rab proteins with the C-terminal sequence -XXCC, -XCXC and -CCXX, such as RAB1A, RAB3A, RAB5A and RAB7A. Publication Abstract from PubMedProtein prenylation is essential for many cellular processes including signal transduction, cytoskeletal reorganization, and membrane trafficking. Here, we identify a novel type of protein prenyltransferase, which we named geranylgeranyltransferase type-III (GGTase-III). GGTase-III consists of prenyltransferase alpha subunit repeat containing 1 (PTAR1) and the beta subunit of RabGGTase. Using a biotinylated geranylgeranyl analogue, we identified the Golgi SNARE protein Ykt6 as a substrate of GGTase-III. GGTase-III transfers a geranylgeranyl group to mono-farnesylated Ykt6, generating doubly prenylated Ykt6. The crystal structure of GGTase-III in complex with Ykt6 provides structural basis for Ykt6 double prenylation. In GGTase-III-deficient cells, Ykt6 remained in a singly prenylated form, and the Golgi SNARE complex assembly was severely impaired. Consequently, the Golgi apparatus was structurally disorganized, and intra-Golgi protein trafficking was delayed. Our findings reveal a fourth type of protein prenyltransferase that generates geranylgeranyl-farnesyl Ykt6. Double prenylation of Ykt6 is essential for the structural and functional organization of the Golgi apparatus. A SNARE geranylgeranyltransferase essential for the organization of the Golgi apparatus.,Shirakawa R, Goto-Ito S, Goto K, Wakayama S, Kubo H, Sakata N, Trinh DA, Yamagata A, Sato Y, Masumoto H, Cheng J, Fujimoto T, Fukai S, Horiuchi H EMBO J. 2020 Apr 15;39(8):e104120. doi: 10.15252/embj.2019104120. Epub 2020 Mar , 3. PMID:32128853[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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