Regulation of Oxysterol-binding Protein Golgi Localization through Protein Kinase D–mediated Phosphorylation

• DOI: 10.1091/mbc.e10-02-0090
• Publication Date: 2010-05-06T02:14:25Z
• Authors: Sokha Nhek; Mike Ngo; Xuemei Yang; Michelle M. Ng; Seth J. Field; John M. Asara; Neale D. Ridgway; Alex Toker
• Keywords: Receptors, Steroid; 0303 health sciences; Recombinant Fusion Proteins; Molecular Sequence Data; Golgi Apparatus; Articles; Protein Serine-Threonine Kinases; Cell Line; 03 medical and health sciences; Serine; Animals; Humans; Amino Acid Sequence; Phosphorylation; Sequence Alignment; Protein Kinase C

Protein kinase D (PKD) plays a critical role at the trans-Golgi network by regulating fission of transport carriers destined for plasma membrane. Two known Golgi-localized PKD substrates, PI4-kinase IIIbeta and ceramide transfer protein CERT, mediate signaling to influence vesicle trafficking membrane sphingomyelin synthesis, respectively. is recruited activated Golgi through interaction with diacylglycerol, pool which generated as by-product synthesis from ceramide. Here we identify novel substrate Golgi, oxysterol-binding OSBP. Using substrate-directed phospho-specific antibody that recognizes optimal consensus motif, show phosphorylates OSBP Ser240 in vitro cells. We further phosphorylation occurs Golgi. Phosphorylation does not modulate dimerization, sterol binding, or affinity PI(4)P. Instead, attenuates localization response 25-hydroxycholesterol cholesterol depletion, impairs CERT localization, promotes fragmentation.