Engineering GPI-anchored Proteins in Plant Cells for Enhanced Protein Production and Applications

Arkansas State University Main Campus, Jonesboro AR

Investigators

Abstract

Many therapeutic molecules originate in plants. If their concentration in plants could be increased, perhaps the plants could be eaten directly to administer an effective dose. This is the strategy to be investigated. Engineered plants will produce therapeutic proteins. These proteins will be modified to anchor them to the cell wall. This should increase their dosage within the plant biomass. Each protein will carry a functional module (the GPI anchor) that attaches the protein to the cell wall. This project will provide hands-on learning opportunities for both graduate and undergraduate students at Arkansas State University (A-State). The project will partner with A-State's outreach module “Biotech-in-a-Box”. This serves over 1,000 regional K-12 students each year. Outreach to the public and local K-12 students will foster greater awareness and interest in science and technology. The overall goal is to leverage a unique posttranslational modification, glycosyl-phosphatidyl-inositol (GPI) anchor, to strategically design and engineer novel GPI-anchored proteins (GPI-APs) in plant cells. The objectives are to create protein drugs with enhanced efficacy and to improve the production performance of existing plant cell lines. The proposal outlines three specific research objectives: 1. Investigate the glycosylation and functions of GPI-APs engineered in plant cells; 2. Assess the broader applicability and potential applications of GPI-APs engineering in plant cells; 3. Engineer GPI-APs to improve existing plant cell lines better suited for protein production. The unique GPI anchor structure, comprising a glycan core with a phospholipid tail, is expected to have a significant impact on the biosynthesis and therapeutic properties of anchored proteins. Specifically, the GPI anchor is anticipated to promote intracellular trafficking of anchored proteins in plant cells, leading to the production of glycoprotein with complete and homogeneous glycosylation, and effectively immobilizing or "displaying" proteins on the plasma membrane surface of plant cells. Additionally, it may facilitate the transcellular transport of therapeutic proteins across or into enterocytes, thereby increasing the bioavailability of orally administered biopharmaceuticals. On the other hand, the GPI anchor-mediated “protein surface displaying” feature will be leveraged to modify the structure of plant cell walls, potentially creating new plant cell lines with tailored traits better suited for protein production. This project is jointly supported by the Cellular and Biochemical Engineering Program in ENG/CBET and the Systems and Synthetic Biology Program in BIO/MCB. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.