Chemical screening identifies ROCK1 as a regulator of migrasome formation

Migrasomes are newly discovered cellular organelles, first described in 2015 1 , 2 . Migrasomes are vesicles with diameters of 0.5–3 µm which are generated during cell migration. Cellular contents such as cytosolic components are actively transported to migrasomes and eventually released extracellularly. Thus, migrasomes are proposed as a mechanism for cell–cell communications. Migrasomes are essential for organ morphogenesis during zebrafish embryonic development 3 . Moreover, it has been shown that migrasomes are detected in human serum 4 . Assembly of tetraspanin- and cholesterol-enriched membrane microdomains into micron-scale macrodomains are necessary and sufficient for migrasome formation 5 . In addition, integrins provide the adhesion force for retraction fiber tethering, which are pivotal in migrasome biogenesis process 6 . Pairing of integrins with specific ECM partners for proper adhesion is a determinant for migrasome formation. So far, the systematic studies on detailed regulatory mechanisms of migrasome biogenesis are still lacking.