The Role of BGS13 in Supersecretion in Pichia pastoris

Pichia pastoris is a methylotrophic yeast that has been genetically engineered to express over five thousand heterologous proteins valued for industrial, pharmaceutical, and basic research purposes. Often some proteins are not secreted efficiently from the P. pastoris cell. We have identified a mutant strain disrupted in the BGS13 gene that causes super secretion of many different reporter proteins. Bgs13p is a homolog of Pkc1p, a noted kinase in all eukaryotic cells. Our bgs13 strain contains a hybrid mRNA consisting of pREMI plasmid and a truncated bgs13 sequence which we believe is the cause of the super secretion. Our goal is to determine if this hybrid pREMI-bgs13 is dominant to the normal BGS13. We have expressed the hybrid and the truncated bgs13 mRNA in wild type cells that have the normal BGS13 which produce lipase and human serum albumin reporters. If either the truncated bgs13 or pREMI-bgs13 hybrid is dominant to the wild type BGS13, then we should see elevated secretion of the reporters. Our results illuminate the relationship between the normal BGS13 and the hybrid bgs13. Creating a universal super secretor mutant strain with bgs13 raises the possibility of advancing medical science by enhancing production of life saving recombinant proteins