5jjd

crystal structure of the ceramide transfer protein PH and START domain complex

spinqualitylabelsall models 5jjd, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5jjd is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.403Å Ligands: PEG, PGE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease CERT_HUMAN The disease is caused by variants affecting the gene represented in this entry. Function CERT_HUMAN Shelters ceramides and diacylglycerol lipids inside its START domain and mediates the intracellular trafficking of ceramides and diacylglycerol lipids in a non-vesicular manner. Publication Abstract from PubMed De novo synthesis of the sphingolipid sphingomyelin requires non-vesicular transport of ceramide from the endoplasmic reticulum to the Golgi by the multidomain protein ceramide transfer protein (CERT). CERT's N-terminal pleckstrin homology (PH) domain targets it to the Golgi by binding to phosphatidylinositol 4-phosphate (PtdIns(4)P) in the Golgi membrane, whereas its C-terminal StAR-related lipid transfer domain (START) carries out ceramide transfer. Hyperphosphorylation of a serine-rich motif immediately after the PH domain decreases both PtdIns(4)P binding and ceramide transfer by CERT. This down-regulation requires both the PH and START domains, suggesting a possible inhibitory interaction between the two domains. In this study we show that isolated PH and START domains interact with each other. The crystal structure of a PH-START complex revealed that the START domain binds to the PH domain at the same site for PtdIns(4)P-binding, suggesting that the START domain competes with PtdIns(4)P for association with the PH domain. We further report that mutations disrupting the PH-START interaction increase both PtdIns(4)P-binding affinity and ceramide transfer activity of a CERT-serine-rich phosphorylation mimic. We also found that these mutations increase the Golgi localization of CERT inside the cell, consistent with enhanced PtdIns(4)P binding of the mutant. Collectively, our structural, biochemical, and cellular investigations provide important structural insight into the regulation of CERT function and localization. Interaction between the PH and START domains of ceramide transfer protein competes with phosphatidylinositol 4-phosphate binding by the PH domain.,Prashek J, Bouyain S, Fu M, Li Y, Berkes D, Yao X J Biol Chem. 2017 Aug 25;292(34):14217-14228. doi: 10.1074/jbc.M117.780007. Epub , 2017 Jun 26. PMID:28652409 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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