Possible regulatory network and associated pathways governing the expression of ADH2 in Saccharomyces cerevisiae

With the day to day increase in energy consumption due to increase in urbanization production of bioethanol is highly in demand. At this point where the traditional methods are not able to suffice the demands due to its high cost and low productivity, new methods need to be developed. This review aims to understand the importance and the regulation of ADH2 in Saccharomyces cerevisiae because Adh2p is the only enzyme that initiates the reaction for the conversion of ethanol, the end product of fermentation to acetaldehyde. The effect of glucose on regulatory mechanisms of Alcohol dehydrogenase II (ADH2) with respect to Snf1 kinase, Target of Rapamycin (TOR) and CCR4 (Carbon Catabolite Repression) pathway on S. cerevisiae are discussed. Snf1 is a serine threonine kinase which is inactive in presence of high glucose concentrations and gets activated in low glucose environments which in turn affects the transcription of ADH2 by controlling the upstream TFs (Transcription Factors). TOR pathway is an essential signalling network that senses the availability of nutrients, mostly glucose and amino acids. This gets activated in presence of glucose. TORC1 regulates the transcription of ADH2 via various downstream transcription factors like Sch9p, Rim15, etc. Another global transcription factor CCR4, regulates ADH2 by acting directly upon its promoter region. The unique function of Adh2p in yeast metabolism, has directed numerous research work making it a vital target. Genetic manipulation of ADH2 gene has proved to be beneficial for food, bioethanol industry.