Organization of Protein Tyrosine Kinase-7 on Cell Membranes Characterized by Aptamer Probe-Based STORM Imaging.

Protein tyrosine kinase-7 (PTK7), as an important membrane receptor, regulates various cellular activities, including cell polarity, movement, migration, and invasion. Although lots of research studies focused on revealing its functions from the aspect of the expression of the gene and protein are present, the relationship between the spatial distribution at the single-molecule level and the function remains unclear. Through combining aptamer probe labeling and super-resolution imaging technology, after verifying the specificity and superiority of the aptamer probe, a more significant clustering distribution of PTK7 is found on the MCF10A cell basal membrane than on the apical membrane, which is thought to be related to their specific functions on different membranes. By exploring the relationship between the assembly of PTK7 and lipid rafts, actin cytoskeleton, and carbohydrate chains on the membrane, the unique distribution of PTK7 on disparate membranes is revealed to be probably because of the varied dominant position of these three factors. These findings present the detailed spatial information of PTK7 and the related potential organization mechanism on the cell membrane, which will facilitate a better understanding of the relationship between the molecular assembly and its function, as well as the overall structure of the cell membrane.