Pathways

Rabeprazole is a drug that belongs to the anti secretory drug class. It is used as an anti-ulcer medication, and helps relieve gastric acid reflux, gastric irritation and gastric pain. It inhibits the proton pump action of ATPase, which blocks the final step of gastric acid secretion. The pathway begins in the parietal cell in the stomach, where rabeprazole and a hydrogen ion use the active metabolite in rabeprazole —rabeprazole thioether — to inhibit potassium-transporting ATPase at the secretory surface of the gastric parietal cell. Now in the gastric endothelial cell, these secretory surfaces are inhibited by rabeprazole and by G-Protein signalling cascade through somatostatin receptor type 4, which is activated by somatostatin. At the same time, potassium-transporting ATPase is activated by the G-protein signalling cascade, through histamine H2 receptor, gastrin/cholecystokinin type B receptor, and muscarinic acetylcholine receptor M3 which are activated by histamine, gastrin and acetylcholine, respectively. The potassium transporting ATPase also converts water and ATP to a phosphate molecule and ADP. Alongside the transporters, potassium is brought into the cell. Carbonic anhydrase 1 uses water and carbon dioxide to create hydrogen carbonate and a hydrogen ion, which are both transported out of the endothelial cell, into the gastric lumen. A chloride ion is transported into the gastric endothelial cell through a chloride anion exchanger and is transported out of the cell through a chloride intracellular channel protein 2, back into the gastric lumen.

Rabeprazole is used for the treatment of acid-reflux disorders (GERD), peptic ulcer disease, H. pylori eradication, and prevention of gastrointestinal bleeds with NSAID use. Rabeprazole is a prodrug administered orally but since it degrades rapidly at low pH, the capsule contains enteric-coated granules. After undergoing absorption in the small intestine, it passes from the blood stream into the parietal cells in the stomach, then enters the stomach lumen. It is a weak base and thus, accumulates on the outside of cell in the acidic environment. Its main target is the H+/K+ ATPase in the parietal cells in the stomach. In parietal cells, carbonic anhydrase converts water and carbon dioxide to hydrogen bicarbonate ions and H+. The bicarbonate ions go into the blood via the chloride anion exchanger on the basolateral membrane which exchanges the hydrogen bicarbonate for Cl- ions. There is also the Na+/K+ ATPase which pumps Na+ out of the cell and K+ into the cell. The H+/K+ ATPase is located on the apical membrane and pumps the H+ from the cell into the stomach lumen and K+ from the lumen into the cell. Another transporter, the K+/Cl- symporter transports K+ and Cl- in the stomach lumen. The H+ and Cl- in the stomach lumen forms the HCl acid which, in excess, can cause disorders like ulcers. The acidic environment in the stomach converts the prodrug Rabeprazole into its active form, sulfenamide. Sulfenamide then covalently binds to the cysteine residues on the alpha subunit of the H+/K+ ATPase via disulfide bridges. This binding of sulfenamide irreversibly inhibits the H+/K+ ATPase, preventing too much acid secretion in the stomach. Less acid in the stomach is favorable for symptomatic relief of disorders caused by the acid. Side effects of taking rabeprazole may include headache, diarrhea, constipation, flatulence, rash, sore throat, infection, stomach pain.

Rabeprazole is a drug that belongs to the anti secretory drug class. It is used as an anti-ulcer medication, and helps relieve gastric acid reflux, gastric irritation and gastric pain. It inhibits the proton pump action of ATPase, which blocks the final step of gastric acid secretion. The pathway begins in the parietal cell in the stomach, where rabeprazole and a hydrogen ion use the active metabolite in rabeprazole —rabeprazole thioether — to inhibit potassium-transporting ATPase at the secretory surface of the gastric parietal cell. Now in the gastric endothelial cell, these secretory surfaces are inhibited by rabeprazole and by G-Protein signalling cascade through somatostatin receptor type 4, which is activated by somatostatin. At the same time, potassium-transporting ATPase is activated by the G-protein signalling cascade, through histamine H2 receptor, gastrin/cholecystokinin type B receptor, and muscarinic acetylcholine receptor M3 which are activated by histamine, gastrin and acetylcholine, respectively. The potassium transporting ATPase also converts water and ATP to a phosphate molecule and ADP. Alongside the transporters, potassium is brought into the cell. Carbonic anhydrase 1 uses water and carbon dioxide to create hydrogen carbonate and a hydrogen ion, which are both transported out of the endothelial cell, into the gastric lumen. A chloride ion is transported into the gastric endothelial cell through a chloride anion exchanger and is transported out of the cell through a chloride intracellular channel protein 2, back into the gastric lumen.

Rac1 is signaling protein part of the Rho GTPase family it is involved in cell motility, cell growth and cytoskeletal reorganization. Rac1 activity is regulated by guanine nucleotide exchange factors (GEFs). GEFs cause the release of GDP, allowing GDP to bind and Rac1 to become activated. GTPase-activated proteins (GAPs) down regulate the activity of GEFs be stimulating the inactivation via binding of GDP to Rac1. Active Rac1 stimulates proteins (ie. Wiskott–Aldrich syndrome) leading to actin polymerization. Actin polymerization is also regulated by cofilin. PAK proteins are critical effectors to cytoskeleton reorganization. PAK1 phosphorylates and activates LIM kinase. LIM kinase then phosphorylates cofilin, inactivating it leading to reduced actin filament severing and depolymerization, therby increasing polymerized actin. Rac1 stimulates lamellipodia and filopodia formation which are involved in cell movement and sensing the environment. It is proposed that PAK1 is involved in the phosphorylation of myosin light chain affecting myosin light chain phosphorylation.

Rac1 is signaling protein part of the Rho GTPase family it is involved in cell motility, cell growth and cytoskeletal reorganization. Rac1 activity is regulated by guanine nucleotide exchange factors (GEFs). GEFs cause the release of GDP, allowing GDP to bind and Rac1 to become activated. GTPase-activated proteins (GAPs) down regulate the activity of GEFs be stimulating the inactivation via binding of GDP to Rac1. Active Rac1 stimulates proteins (ie. Wiskott–Aldrich syndrome) leading to actin polymerization. Actin polymerization is also regulated by cofilin. PAK proteins are critical effectors to cytoskeleton reorganization. PAK1 phosphorylates and activates LIM kinase. LIM kinase then phosphorylates cofilin, inactivating it leading to reduced actin filament severing and depolymerization, therby increasing polymerized actin. Rac1 stimulates lamellipodia and filopodia formation which are involved in cell movement and sensing the environment. It is proposed that PAK1 is involved in the phosphorylation of myosin light chain affecting myosin light chain phosphorylation.

Rac1 is signaling protein part of the Rho GTPase family it is involved in cell motility, cell growth and cytoskeletal reorganization. Rac1 activity is regulated by guanine nucleotide exchange factors (GEFs). GEFs cause the release of GDP, allowing GDP to bind and Rac1 to become activated. GTPase-activated proteins (GAPs) down regulate the activity of GEFs be stimulating the inactivation via binding of GDP to Rac1. Active Rac1 stimulates proteins (ie. Wiskott–Aldrich syndrome) leading to actin polymerization. Actin polymerization is also regulated by cofilin. PAK proteins are critical effectors to cytoskeleton reorganization. PAK1 phosphorylates and activates LIM kinase. LIM kinase then phosphorylates cofilin, inactivating it leading to reduced actin filament severing and depolymerization, therby increasing polymerized actin. Rac1 stimulates lamellipodia and filopodia formation which are involved in cell movement and sensing the environment. It is proposed that PAK1 is involved in the phosphorylation of myosin light chain affecting myosin light chain phosphorylation.

Rac1 is signaling protein part of the Rho GTPase family it is involved in cell motility, cell growth and cytoskeletal reorganization. Rac1 activity is regulated by guanine nucleotide exchange factors (GEFs). GEFs cause the release of GDP, allowing GDP to bind and Rac1 to become activated. GTPase-activated proteins (GAPs) down regulate the activity of GEFs be stimulating the inactivation via binding of GDP to Rac1. Active Rac1 stimulates proteins (ie. Wiskott–Aldrich syndrome) leading to actin polymerization. Actin polymerization is also regulated by cofilin. PAK proteins are critical effectors to cytoskeleton reorganization. PAK1 phosphorylates and activates LIM kinase. LIM kinase then phosphorylates cofilin, inactivating it leading to reduced actin filament severing and depolymerization, therby increasing polymerized actin. Rac1 stimulates lamellipodia and filopodia formation which are involved in cell movement and sensing the environment. It is proposed that PAK1 is involved in the phosphorylation of myosin light chain affecting myosin light chain phosphorylation.

Rac1 is signaling protein part of the Rho GTPase family it is involved in cell motility, cell growth and cytoskeletal reorganization. Rac1 activity is regulated by guanine nucleotide exchange factors (GEFs). GEFs cause the release of GDP, allowing GDP to bind and Rac1 to become activated. GTPase-activated proteins (GAPs) down regulate the activity of GEFs be stimulating the inactivation via binding of GDP to Rac1. Active Rac1 stimulates proteins (ie. Wiskott–Aldrich syndrome) leading to actin polymerization. Actin polymerization is also regulated by cofilin. PAK proteins are critical effectors to cytoskeleton reorganization. PAK1 phosphorylates and activates LIM kinase. LIM kinase then phosphorylates cofilin, inactivating it leading to reduced actin filament severing and depolymerization, therby increasing polymerized actin. Rac1 stimulates lamellipodia and filopodia formation which are involved in cell movement and sensing the environment. It is proposed that PAK1 is involved in the phosphorylation of myosin light chain affecting myosin light chain phosphorylation.

Rac1 is signaling protein part of the Rho GTPase family it is involved in cell motility, cell growth and cytoskeletal reorganization. Rac1 activity is regulated by guanine nucleotide exchange factors (GEFs). GEFs cause the release of GDP, allowing GDP to bind and Rac1 to become activated. GTPase-activated proteins (GAPs) down regulate the activity of GEFs be stimulating the inactivation via binding of GDP to Rac1. Active Rac1 stimulates proteins (ie. Wiskott–Aldrich syndrome) leading to actin polymerization. Actin polymerization is also regulated by cofilin. PAK proteins are critical effectors to cytoskeleton reorganization. PAK1 phosphorylates and activates LIM kinase. LIM kinase then phosphorylates cofilin, inactivating it leading to reduced actin filament severing and depolymerization, therby increasing polymerized actin. Rac1 stimulates lamellipodia and filopodia formation which are involved in cell movement and sensing the environment. It is proposed that PAK1 is involved in the phosphorylation of myosin light chain affecting myosin light chain phosphorylation.