1.1.3 Phosphorylation of 5-LOX at different sites determine its pro-inflammatory or anti-inflammatory properties  
 
2.Sites of phosphorylation in 5-LOX
The 5-LOX protein has three nuclear import sequences that can be regulated and function independently from one another. (a)
2.1  271
2.2  523
2.3  others
  Ser663  :extracellular signal-regulated kinase (ERK) 1/2 were identified as 5-LO kinases that phosphorylate 5-LO in vitro at Ser663,and mediate cellular activation of 5-LO
List them in a table to make a comparison
Sites
Genetic motif
Effects when phosphorylated
Extra
Reference
271
 R–X–X–S motif
 mediate the activation of 5-LO.Phosphorylated Ser-271 5-LO was exclusively found in the nucleus,serves to interfere with exportin-1-mediated nuclear export
 
 \cite{Werz_2005}\cite{Flamand_2008}
523
 
 reduce 5-LO enzyme activity.    The 5LO phosphorylation at Ser523 prevents the perinuclear membranous shift of 5LO and,thus, the production of LTB4 decrease.    
 
 \cite{Luo_2004} (Ye 2008)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Ser271与Ser23两位点磷酸化的合作:the phosphorylation of Ser-271 serves to inhibit the nuclear export of 5-LO. This action works in concert with nuclear import, which is regulated by phosphorylation on Ser-523, to determine the subcellular distribution of 5-LO, which in turn regulates leukotriene biosynthesis.\cite{Flamand_2008}
 
3.Adjustment of the phosphorylation of 5-LOX 
1.        3.1          Activation of 5-LOX by phosphorylation 
      p38 mitogen-activated protein kinase (MAPK)-regulated mitogen-activated protein kinase-activated protein kinases (MAPKAPKs, MKs) and extracellular signal-regulated kinase (ERK) 1/2 were identified as 5-LO kinases that phosphorylate 5-LO in vitro at Ser271 and Ser663, respectively, and mediate cellular activation of 5-LO\cite{Werz_2000}\cite{Werz_2002}Agents that induce LT synthesis, i.e. ionophore and fMLP as well as TNFa, GM-CSF, LPS and phorbol esters that prime leukocytes for enhanced LT synthesis, activate ERKs, p38 MAPK and downstream MKs in leukocytes. Therefore, these stimuli could activate 5-LO for product formation via enzyme phosphorylation by ERKs and p38 MAPK-regulated MKs. Furthermore, both phosphorylation reactions seem to induce nuclear translocation of 5-LO\cite{Luo_2003}\cite{Boden_2000} cell stress(such as osmotic shock,genotoxic stress (sodium arsenite (SA)), UV light and heat shock) strongly enhances cellular 5-LO activity and activates p38 MAPK as well as downstream MKs, and inhibition of p38MAPK by SB203580 abolishes stress-induced LT synthesis in BL41-E95-A cells without inhibition of 5-LO catalytic activity in cell free systems. In human PMNL, stimulation of p38 MAPK and MKs by cell stress itself (no further stimulus) is sufficient to activate 5-LO. In contrast to simulation with Ca2+-mobilizing agents like ionophore A23187, the stress-induced activation of 5-LO and of p38MAPK occurs also after Ca2+ depletion and the p38 MAPK inhibitor SB203580 blocks stress-induced 5-LO product formation more efficiently than ionophore- or thapsigargin-induced formation of 5-LO products\cite{Werz_2001}
  CaMKII and protein kinase A (PKA) also phosphorylate Ser271 in vitro, although only at low level. Recently, it was found that PKA activation inhibits 5-LO translocation and LT biosynthesis in human neutrophils \cite{Luo_2004}\cite{Flamand_2002}. PKA phosphorylates 5-LO at Ser523 which reduces cellular enzyme activity and also decreases activity of the recombinant enzyme in vitro.
     
1.        3.1          Inhibition of 5-LOX by phosphorylation 
The 5LO phosphorylation at Ser523 prevents the membranous shift of 5LO and, thus, the production of LTB4.   \cite{Ye_2008}      
Ser523 is localized at the periphery of the catalytic domain and phosphorylation of this residue may cause allosteric changes that reduce 5-LO enzyme activity \cite{Luo_2004}, and might alter binding of 5-LO inhibitors to the enzyme.The phosphorylated 5LO (P-5LO) is not shifted to the perinuclear membrane and, therefore, cannot use AA to produce LT. Instead, it interacts with COX2 in the cytoplasm, producing 15epi-LXA4 is probably modified by S-nitrosylation at Cys526 from the 15R-HETE that is generated by COX2, which by inducible NO synthase    \cite{Birnbaum_2007}\cite{Birnbaum_2007}\cite{R_dmark_2005} .    The peroxisome proliferator-activated receptor γ agonist pioglitazon(PIO) and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, atorvastatin(ATV) ,in addition to up-regulating the expression and activity of cPLA2 and COX2,    \cite{Birnbaum_2007}    enhance 5LO phosphorylation at Ser523 by PKA, PIO plus ATV increased translocation of 5LO into the cytosolic fraction and prevented shift of 5LO to the membranes, leading to enhanced 15-epi-LXA4 production; 2) inhibiting PKA with H-89 prevented 5LO phosphorylation by PIO plus ATV and caused shift of 5LO to the membranes, resulting in enhanced production of LTs instead of 15-epi-LXA4 ,the production of 15-epi-LXA4 occurs by interaction between COX2 and 5LO in the cytosolic fraction, whereas the production of LT occurs by an interaction of cPLA2 and 5LO on the membranous fraction of the cell .PIO and ATV did not affect total 5LO concentration, but they increased myocardial levels of Ser523 P-5LO, whereas H-89 alone did not affect total 5LO or P-5LO levels; however, it completely blocked the increase in P-5LO by both PIO and ATV  \cite{Ye_2008}       
List the activators and inhibitors in a table
Inhibitors/Activators
Target Sites
 Release of AA
Translocation of 5-LOX
Reference
                           Extra
MK-886
GluR1at Ser831 and Ser845
Increase
Cytosolic-->endoplasmic, Golgi and nuclear membranes
\cite{M_nard_2005}\cite{Murphy_2007}
 
p38 MAPK inhibitor SB203580 
 MAPKAPKs, MKs,Ser271
inhibit 
 
  \cite{Werz_2000}\cite{Werz_2002}
 MKs and ERKs, 5-LO kinases, mediate activitation of 5-LO,not lead to sub-stantial increases in [Ca2+]i,but also can act together with Ca2+ to activate 5-LO
 U0126(inhibitor)     ERKs,Ser663         ERKs,Ser663             
inhibit 
 
                                \cite{Werz_2000}\cite{Werz_2002}
            
  pioglitazon + atorvastatin (Activitor)
 Ser523,no clear      \cite{Ye_2008} 
             prevented shift  of 5LO  to the membranes , enhanced 15-epi-LXA4 production by 5LO interacted with COX2 in the cytosolic fraction