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A Cyclooxygenase-2-dependent Prostaglandin E2 Biosynthetic System in the Golgi Apparatus
- Source :
- Journal of Biological Chemistry. 290:5606-5620
- Publication Year :
- 2015
- Publisher :
- Elsevier BV, 2015.
-
Abstract
- Cyclooxygenases (COXs) catalyze the committed step in prostaglandin (PG) biosynthesis. COX-1 is constitutively expressed and stable, whereas COX-2 is inducible and short lived. COX-2 is degraded via endoplasmic reticulum (ER)-associated degradation (ERAD) following post-translational glycosylation of Asn-594. COX-1 and COX-2 are found in abundance on the luminal surfaces of the ER and inner membrane of the nuclear envelope. Using confocal immunocytofluorescence, we detected both COX-2 and microsomal PGE synthase-1 (mPGES-1) but not COX-1 in the Golgi apparatus. Inhibition of trafficking between the ER and Golgi retarded COX-2 ERAD. COX-2 has a C-terminal STEL sequence, which is an inefficient ER retention signal. Substituting this sequence with KDEL, a robust ER retention signal, concentrated COX-2 in the ER where it was stable and slowly glycosylated on Asn-594. Native COX-2 and a recombinant COX-2 having a Golgi targeting signal but not native COX-1 exhibited efficient catalytic coupling to mPGES-1. We conclude that N-glycosylation of Asn-594 of COX-2 occurs in the ER, leading to anterograde movement of COX-2 to the Golgi where the Asn-594-linked glycan is trimmed prior to retrograde COX-2 transport to the ER for ERAD. Having an inefficient ER retention signal leads to sluggish Golgi to ER transit of COX-2. This permits significant Golgi residence time during which COX-2 can function catalytically. Cytosolic phospholipase A2α, which mobilizes arachidonic acid for PG synthesis, preferentially translocates to the Golgi in response to physiologic Ca(2+) mobilization. We propose that cytosolic phospholipase A2α, COX-2, and mPGES-1 in the Golgi comprise a dedicated system for COX-2-dependent PGE2 biosynthesis.
- Subjects :
- Glycosylation
Leupeptins
KDEL
Immunoblotting
Golgi Apparatus
Cysteine Proteinase Inhibitors
Biology
Endoplasmic Reticulum
Biochemistry
Dinoprostone
Mice
chemistry.chemical_compound
symbols.namesake
Animals
Humans
Inner membrane
Amino Acid Sequence
Protein Kinase Inhibitors
Molecular Biology
COPII
Prostaglandin-E Synthases
Sulfonamides
Microscopy, Confocal
Group IV Phospholipases A2
Endoplasmic reticulum
fungi
food and beverages
Golgi Targeting
ER retention
Endoplasmic Reticulum-Associated Degradation
Cell Biology
Fibroblasts
Golgi apparatus
Isoquinolines
Cell biology
Intramolecular Oxidoreductases
Protein Transport
HEK293 Cells
chemistry
Cyclooxygenase 2
Mutation
NIH 3T3 Cells
symbols
Asparagine
Signal Transduction
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 290
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....a2c9465cdb16dde1e6dbc92923d66045