Overexpression of the regulatory subunit of protein kinase A increases heterologous protein expression in Pichia pastoris

Translational regulation plays an important role in protein synthesis. Our goal is to screen translation-related factors to improve heterologous protein expression in Pichia pastoris.28 translation-related factors were overexpression in P. pastoris GS115 expressing enhanced green fluorescent protein (eGFP). The results showed that overexpression of Bcy1, which is the regulatory subunit of protein kinase A (PKA), significantly increased both eGFP expression and cell biomass by 20% in methanol induction for 120 hours. Also, overexpression of Bcy1 contributed to elevating the growth rate by 18% and improving the production of industrial enzyme Phytase (Phy) by 26%. Transcriptome analysis indicated that the overall expression of ribosomal protein genes was significantly down-regulated and post-diauxic shift genes and stress response element genes were up-regulated with the lower PKA activity.Bcy1 regulates ribosome protein genes, post-diauxic shift genes and stress response element genes by decreasing the PKA activity leading to improving cell growth and heterologous protein expression. This study provides a convenient and universal factor for heterologous protein production.