The phosphorylation state of a given protein is governed by the balance between protein kinases that transfer phosphate from adenosine triphosphate (ATP) to the protein (phosphorylation) and protein phosphatase that catalyzes the reverse reaction (dephosphorylation). It is now widely acknowledged that the regulation of protein phosphorylation requires coordinated control of both kinases and phosphatases. The effect of ethanol exposure on protein phosphatase expression and activity is still not known. However, phosphatase inhibitors alter the function of GABAA receptors by reducing GABAA receptor rundown (Huang and Dillon 1998). In addition, blockade of phosphatase activity during preparation of cerebral cortical synaptoneurosomes decreases muscimol-induced Cl− uptake (Kumar et al. 2005). Hence, the balance between phosphatase and kinase activity is important for GABAA receptor function. Further studies on the effects of ethanol on protein phosphatase activity are warranted.
