Abstract: As one of the largest superfamilies of membrane transport proteins,Major Facilitator Superfamily（MFS）included more than 1 million sequenced members. MFS,with a majority of members contained 400-600 amino acid residues,has been expanded to 95 families according to Transporter Classification Database（TCDB）. MFS promoted the transport of solutes such as sugars,drug molecules,peptides,metabolites of tricarboxylic acid cycle,organic anions,and inorganic anions across the cell membrane in response to electrochemical gradient. Recently,there have been more and more studies focusing on the crystal structure and transport mechanism of MFS. Usually,the MFS were reported to have 12 transmembrane helical segments and special fold method called MFS fold. Like a “rocker switch”,MFS proteins exhibited intracellular and extracellular open or closed conformations to transport the solute. In addition,there were many studies focusing on the physiological functions of MFS in animals and plants. At present,the MFS transporter of human was increasingly concerned as their distinctive physiological functions. For example,the deletion of some members of MFS might lead to brain shrinkage and developmental delay. Besides,some MFS proteins were also reported to regulate acid-base balance of cells,promote the absorption of anti-cancer and anti-inflammatory drugs. Overall,the study of human MFS transporters provided the basis for the occurrence and prevention of many diseases such as diabetes,fatigue syndrome,cardiovascular disease,and cancer. In this study,to provide theory basis for further study of MFS,the development of MFS,its crystal structure,transport mechanism and physiological function were reviewed,and on such a basis,the development trend of MFS was also prospected.

Key words: MFS, structure, transport, physiological function