New Insights on How Cellulose is Built Could Indicate How to Break it Apart for Biofuels

Cellulose is a compound used in a variety of materials. Ying Gu, associate professor of biochemistry and molecular biology at The Pennsylvania State University (Penn State) said that cellulose makes up about 95 percent paper and 90 percent cotton, and its derivatives are even used as emulsifiers in ice cream.

Cellulose has also been considered as a major component of biofuels, and the knowledge of cellulose synthesis could help optimize its use as a renewable energy resource. Penn State researchers have identified the major steps in the process as well as the tools that plant cells use to create cellulose, including proteins that transport critical components to the location where cellulose is made.

Gu said that it has been known that cellulose is synthesized in the plasma membrane that surrounds plant cells called the cellulose synthase complex, and that the main component of this complex is a unique cargo protein called cellulose synthase. What is unknown is, if other proteins are involved in the complex, or how the proteins get to the plasma membrane. To answer these questions, the researchers used different approaches to create a timeline of events and to identify the main proteins involved in preparing the cell for synthesis.

The researchers showed that a protein called cellulose synthase interactive 1 (CSI1) interacts with the cellulose synthase complex before synthesis and may help mark the site at the plasma membrane where synthesis occurs. They also demonstrated that CSI1 interacts with a separate complex called the exocyst complex, which is involved in transporting materials to the plasma membrane in a variety of species, and a protein called PATROL1. These components may contribute to how quickly the cellulose synthase complex travels to the cell's outer membrane before synthesis. Because CSI1 interacts with many components that are important to cellulose synthesis, the research team plans to use it as a tool to further explain this important process and its evolution.

For more details, read the Penn State SCIENCE.