When you see the lovely images on the cover of a journal, you can be sure that those images are the tip of the iceberg for a cell biologist's “portfolio” of images. Today’s image complements the cover and accompanying paper in this month’s Journal of Biological Chemistry and deserves its own spotlight (yes, I’m referring to HighMag as a “spotlight”).
The myosin family of actin motors is large and diverse. One myosin, Myo3A, is found in the stereocilia of the inner ear and has an unconventional structure. Quintero and colleagues recently found that the kinase domain of Myo3a autophosphorylates the motor domain, which alters the localization of Myo3A and decreases the formation of actin protrusions called filopodia in cultured cells. The authors suggest that the function and localization of Myo3A in other bundled actin structures, like stereocilia, are regulated by this auto-inhibition mechanism. Image above shows the actin-binding protein espin (purple) and a mutant form of Myo3A that lacks the kinase domain (white) in a cultured cell.