Peroxisomes in Focus: Illuminating Organelle Function with Microscopy

Interns

Giovanni Ledoux - Pharmacology

Yuying Huang - Pharmacology

Miko Curtis - Psychological & Brain Sciences

Jasmin Lin - Chemical Engineering

Project Description

A peroxisome is a cell organelle responsible for breaking down fats within the body and protecting cells from damage. Healthy peroxisomes contain enzymes that perform a specific function for the cell. To carry out these functions, peroxisomes require an important enzyme called catalase that must be delivered to the organelle by another protein called PEX5. Each delivery of catalase causes PEX5 to get trapped in the inside of the peroxisome, and it needs to be recycled for more catalase to be delivered correctly. The proteins PEX1 and PEX6 are critical to recycle PEX5 and enable the continued delivery of catalase to peroxisomes. Mutations in PEX1 are the most common cause of a group of severe developmental disorders in infants. In this project, PEX1 protein is re-introduced to mutated cells to rehabilitate peroxisome health and prevent these disorders. To test this, cell membranes were made accessible to dyed antibodies, which were used to label specific proteins within the cells in different colors. This made them observable under the fluorescent microscope. Under magnification, the functionality of the peroxisome was assessed based on the location of a peroxisome membrane protein (PMP70) and the enzyme catalase. There was a strong overlap of the PMP70 and catalase fluorescent labels in the cells that had PEX1 reintroduced to them. Such overlap indicates success in partially remedying the damage that PEX1 mutations cause, and presents possibilities for future medical treatments.