3KN1: Crystal Structure of Golgi Phosphoprotein 3 N-term Truncation Variant

Citation:
Abstract
Targeting and retention of resident integral membrane proteins of the Golgi apparatus underly the function of the Golgi in glycoprotein and glycolipid processing and sorting. In yeast, steady-state Golgi localization of multiple mannosyltransferases requires recognition of their cytosolic domains by the peripheral Golgi membrane protein Vps74, an orthologue of human GOLPH3/GPP34/GMx33/MIDAS (mitochondrial DNA absence sensitive factor). We show that targeting of Vps74 and GOLPH3 to the Golgi apparatus requires ongoing synthesis of phosphatidylinositol (PtdIns) 4-phosphate (PtdIns4P) by the Pik1 PtdIns 4-kinase and that modulation of the levels and cellular location of PtdIns4P leads to mislocalization of these proteins. Vps74 and GOLPH3 bind specifically to PtdIns4P, and a sulfate ion in a crystal structure of GOLPH3 indicates a possible phosphoinositide-binding site that is conserved in Vps74. Alterations in this site abolish phosphoinositide binding in vitro and Vps74 function in vivo. These results implicate Pik1 signaling in retention of Golgi-resident proteins via Vps74 and show that GOLPH3 family proteins are effectors of Golgi PtdIns 4-kinases.
PDB ID: 3KN1Download
MMDB ID: 78794
PDB Deposition Date: 2009/11/11
Updated in MMDB: 2009/12
Experimental Method:
x-ray diffraction
Resolution: 2.9  Å
Source Organism:
Similar Structures:
Biological Unit for 3KN1: monomeric; determined by author
Molecular Components in 3KN1
Label Count Molecule
Protein (1 molecule)
1
Golgi Phosphoprotein 3(Gene symbol: GOLPH3)
Molecule annotation
Chemicals (6 molecules)
1
6
* Click molecule labels to explore molecular sequence information.

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