Premium
Spatial Regulation of Golgi Phosphatidylinositol‐4‐Phosphate is Required for Enzyme Localization and Glycosylation Fidelity
Author(s) -
Cheong Fei Ying,
Sharma Vandana,
Blagoveshchenskaya Anastasia,
Oorschot Viola M. J.,
Brankatschk Ben,
Klumperman Judith,
Freeze Hudson H.,
Mayinger Peter
Publication year - 2010
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2010.01092.x
Subject(s) - golgi apparatus , biology , microbiology and biotechnology , gene knockdown , phosphatidylinositol , glycosylation , phosphatase , biochemistry , endoplasmic reticulum , phosphorylation , gene
The enrichment of phosphatidylinositol‐4‐phosphate (PI(4)P) at the trans Golgi network (TGN) is instrumental for proper protein and lipid sorting, yet how the restricted distribution of PI(4)P is achieved remains unknown. Here, we show that lipid phosphatase Suppressor of actin mutations 1 (SAC1) is crucial for the spatial regulation of Golgi PI(4)P. Ultrastructural analysis revealed that SAC1 is predominantly located at cisternal Golgi membranes but is absent from the TGN, thus confining PI(4)P to the TGN. RNAi‐mediated knockdown of SAC1 caused changes in Golgi morphology and mislocalization of Golgi enzymes. Enzymes involved in glycan processing such as mannosidase‐II (Man‐II) and N ‐acetylglucosamine transferase‐I (GnT‐I) redistributed to aberrant intracellular structures and to the cell surface in SAC1 knockdown cells. SAC1 depletion also induced a unique pattern of Golgi‐specific defects in N ‐and O ‐linked glycosylation. These results indicate that SAC1 organizes PI(4)P distribution between the Golgi complex and the TGN, which is instrumental for resident enzyme partitioning and Golgi morphology.