For a long time glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was considered a classical glycolytic protein of little interest. It was also used as a model protein for analysis of protein structure and enzyme mechanisms. However, recent evidence demonstrates that GAPDH from mammalian cells displays a number of diverse activities unrelated to its glycolytic function. This enzyme is an example of moonlighting protein. Dehydrogenase participates in membrane fusion, microtubule assembly, vesicular transport, and the maintenance of DNA integrity. New and novel studies indicate that enzyme is directly involved in transcriptional, posttranscriptional gene regulation, and the maintenance of chromatin structure. Furthermore, other studies also indicate a role of GAPDH in apoptosis, and age-related neurodegenerative disease e.g. Alzheimer's, Huntington's and Parkinson's diseases. This work describes the structure and localization of GAPDH in cells as well as the latest discoveries on the multifunctional properties of the enzyme.