Improving Endosomal Escape and Cytosolic Delivery of Macromolecules by Employing Calcium Dependent Cell Penetrating Peptide
Disciplines
Biochemistry | Cell Biology | Molecular Biology
Abstract (300 words maximum)
Cell-penetrating peptides (CPPs) can effectively transport macromolecules across the cellular membrane and into the cell’s interior. However, many CPP’s rely on covalent bonding to traffic their cargo into the cell. This covalent bonding is thought to lower the endosomal escape of cargo, therefore encouraging aggregation of cargo within the endosomes and decreasing the effective cytosol diffusion of the cargo. Our goal was to test the functionality of a novel CPP, TAT-calmodulin (TAT-CaM), which utilizes calcium dependent, non-covalent bonding to transport its cargo. It was hypothesized that TAT-CaM would exhibit greater endosomal escape and increased cytosolic deliver of cargo. Images of fluorescently labeled cargo were captured by confocal microscopy in BHK21 cells to visualize the difference between these two cargo carriers. Results showed an increased level of diffuse signal in TAT-CaM positive images, while cargo trafficked using the covalently bound carrier displayed a punctate like signal pattern throughout the cells. Therefore, we conclude that TAT-CaM enhances endosomal escape and cytosolic delivery of cargo.
Academic department under which the project should be listed
CSM - Molecular and Cellular Biology
Primary Investigator (PI) Name
Dr. Jonathan McMurry
Improving Endosomal Escape and Cytosolic Delivery of Macromolecules by Employing Calcium Dependent Cell Penetrating Peptide
Cell-penetrating peptides (CPPs) can effectively transport macromolecules across the cellular membrane and into the cell’s interior. However, many CPP’s rely on covalent bonding to traffic their cargo into the cell. This covalent bonding is thought to lower the endosomal escape of cargo, therefore encouraging aggregation of cargo within the endosomes and decreasing the effective cytosol diffusion of the cargo. Our goal was to test the functionality of a novel CPP, TAT-calmodulin (TAT-CaM), which utilizes calcium dependent, non-covalent bonding to transport its cargo. It was hypothesized that TAT-CaM would exhibit greater endosomal escape and increased cytosolic deliver of cargo. Images of fluorescently labeled cargo were captured by confocal microscopy in BHK21 cells to visualize the difference between these two cargo carriers. Results showed an increased level of diffuse signal in TAT-CaM positive images, while cargo trafficked using the covalently bound carrier displayed a punctate like signal pattern throughout the cells. Therefore, we conclude that TAT-CaM enhances endosomal escape and cytosolic delivery of cargo.