Cell-Sonar, a Novel Method for Intracellular Tracking of Secretory Pathways

Intracellular tracking is commonly used in trafficking research. Until today, the respective techniques have remained complex, and complicated, mostly transgenic target protein changes are necessary, often requiring expensive equipment and expert knowledge.

We present a novel method, which we term "cell-sonar", that enables the user to track expression changes of specific protein markers that serve as points of interaction. Our study provides comparable analyses of expression changes of these marker proteins by in-cell Western analyses in two otherwise isogenic cell lines that only differ in the overexpression of the tracked target protein. Using the overexpressed human adult muscle-type nicotinic acetylcholine receptor as an example, we demonstrate that cell-sonar can cover multiple intracellular compartments such as the endoplasmic reticulum, the pathway between it and the Golgi apparatus, and the endocytic pathway.

We provide evidence for receptor maturation in the Golgi and storage in recycling endosomes, rather than the fate of increased insertion into the plasma membrane. Additionally, we demonstrate with the implementation of nicotine that the receptor's destiny is exasperated up to secondary degradation.

Cell-sonar is an affordable, easy-to-implement, and cheap method that can be adapted to a broad variety of proteins and cellular pathways of interest to researchers.