Topic: Glut4 Storage Vesicles

We have recently identified Tusc5 as a Retinal Ganglion Cell (RGC) marker, specifically expressed in Brn3a+ RGCs, and absent from Brn3aKO retinas. Tusc5 is a transmembrane protein that assists trafficking of Glucose transporter GluT4 in adipocites. GluT4 are continuously recycled through endosomes from and to the plasma membrane and stored in GSVs (Glut4 Storage Vesicles), in an insulin-dependent manner. In adipocites, GluT4 recycling is assisted by Tusc5. In mouse retina, Tusc5 is expressed specifically in a subset of Brn3a+ retinal ganglion cells (RGCs), characterized by small dense “bushy”

Tusc5 is a transmembrane protein that assists trafficking of Glucose transporters molecules in adipocites. We and others have previously described Tusc5 in projection sensory neurons. Glut4 transporters (localized in muscles and adipocytes) are continuously recycled through endosomes from and to the plasma membrane and stored in GSVs (Glut4 Storage Vesicles). In adipocites, Tusc5 follows Glut4 trafficking between GSVs and cell surface, upon insulin stimulation. Tusc5 interacts with the signaling cascade of fusion of GSVs with the plasma membrane, similar to the exocytosis mechanism in neuronal