in photosynthetic thylakoid membranes occurs at elevated temperatures, directly impacting the desphosphorylation of key proteins within the photosystem II complex. Role of dephosphorylation in disease Pathology Excessive dephosphorylation of the membrane ATPases and proton pumps in the gastrointestinal tract leads to higher secretory rates of caustic peptic acids. These result in heartburn and esophagitis. In combination with Helicobacter pylori infection, peptic ulcer disease is caused by the elevated pH dephosphorylation elicits. The microtubule-associated protein tau is abnormally hyperphosphorylated when isolated from the brain of patients who suffer from Alzheimer's disease. This is due to the dysfunction of dephosphorylation mechanisms at specific amino acids on the tau protein. Tau dephosphorylation is catalysed by protein phosphatase-2A and phosphatase-2B. Deficiency or modification of one or both proteins may be involved in abnormal phosphorylation of tau in Alzheimer's disease Dephosphorylation has also been linked to cardiac disease, particularly the alteration of actin-myosin interactions that are key for providing the underlying force of a heartbeat. Dephosphorylation is a key part of the myosin cycling kinetics that directly control the actin-myosin interactions. When the dephosphorylation process is interrupted, calcium dependent cardiac contraction is impaired or fully disabled. Research has also suggested that modifications to dephosphorylation impact physiological processes implicated in Diabetes mellitus. The kinetics of dephosphorylation of insulin receptor substrate-1/2, Akt, and ERK1/2, phosphoproteins are shown to be involved in insulin receptor signaling, and in vitro models demonstrate that changes to dephosphorylation kinetics impact upstream and downstream insulin stimulation. Treatments Inhibition of proton pumps significantly decreases the acidity of the gastrointestinal tract, reducing the symptoms of acid-related diseases. The resulting change in pH decreases survival of the bacteria H.pylori, a major cause of peptic ulcer disease. Once the proton pump inhibitor eradicates this bacteria within the gut, reversing erosive reflux. Treating heart disease has improved with the use of drugs that inhibit AMPK via dephosphorylation. In the treatment of diabetes, sulfonylurea drugs are able to stimulate dephosphorylation of the glucose transporter GLUT4, decreasing insulin resistance and increasing and glucose utilization. Research applications Dephosphorylation can play a key role in molecular biology, particularly cloning using restriction enzymes. The cut ends of a vector may re-ligate during a ligation step due to phosphorylation. By using a desphosphorylating phosphatase, re-ligation can be avoided. Alkaline phosphatases, which remove the phosphate group present at the 5′ terminus of a DNA molecule, are often sourced naturally, most commonly from calf intestine, and