title: Enhanced protein secretion from insect cells by co-expression of the chaperone calreticulin and translation initiation factor eIF4E.
abstract: Host protein synthesis is shut down in the lytic baculovirus expression vector system (BEVS). This also affects host proteins involved in routing secretory proteins through the endoplasmic reticulum (ER)-Golgi system. It has been demonstrated that a secretory alkaline phosphatase-EGFP fusion protein (SEFP) can act as a traceable and sensitive secretory reporter protein in BEVS. In this study, a chaperone, calreticulin (CALR), and the translation initiation factor eIF4E were co-expressed with SEFP using a bicistronic baculovirus expression vector. We observed that the intracellular distribution of SEFP in cells co-expressing CALR was different from co-expressing eIF4E. The increased green fluorescence emitted by cells co-expressing CALR had a good correlation with the abundance of intracellular SEFP protein and an unconventional ER expansion. Cells co-expressing eIF4E, on the other hand, showed an increase in extracellular SEAP activity compared to the control. Utilization of these baculovirus expression constructs containing either eIF4E or CALR offers a significant advantage for producing secreted proteins for various biotechnological and therapeutic applications.
authors.affiliation: Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Chao-Yi
authors.initials: CY
authors.lastname: Teng
authors.forename: Shou-Lin
authors.initials: SL
authors.lastname: Chang
authors.forename: Monique M
authors.initials: MM
authors.lastname: van Oers
authors.forename: Tzong-Yuan
authors.initials: TY
authors.lastname: Wu
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics; D000818:Animals; D016367:Baculoviridae / Q000235:genetics*; D037282:Calreticulin / Q000235:genetics* / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics* / Q000378:metabolism; D017930:Genes, Reporter; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D007313:Insecta / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D018832:Molecular Chaperones / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics
chemical_list: D037282:Calreticulin; D039561:Eukaryotic Initiation Factor-4E; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D000469:Alkaline Phosphatase