| Small ubiquitin-like modifier (SUMO) plays a crucial role in many cellular activities, such as regulation of cell cycle, transcription, apoptosis and DNA damage response. SUMOylation pathway is an important mechanism in modifying protein function and regulates protein activities in eukaryotes. Deregulation of SUMOylation pathway is found in many diseases, for instance, neurodegenerative disease, human cancers, heart disease and diabetes. SUMOylation pathway is a three-step process involves a multi-enzyme catalyzed cascade which consists of the following enzymatic steps: activation (E1), conjugation (E2) and ligation (E3). Only some E3 ligation proteins are understood. One of the E3 ligase types have extensively studied is PIAS. It is a protein inhibitor of activated STAT (PIAS1). Intracellular expression of PIAS1 with the bacterial cells does not work well due to the toxicity PIAS1 can create within the cells.;We established two secretion systems to test SUMO- related recombinant proteins expression: Bacteria secretion system and yeast secretion system. We used type II secretion system which includes Sec, Tat and SRP- pathways to secreted recombinant protein production in E.coli K-12 strain. Recombinant proteins also been tested on Pichia pastoris yeast cell line. Since yeast is a eukaryote, it is a suitable host for produce eukaryotic heterologous protein like SUMO-related proteins. |
