A scientist at Sydney's Garvan Institute of Medical Research discovered how insulin activates a motor protein known as myosin IC (Myo1c), which in turn aids in glucose uptake.
Scientists knew that Myo1c was somehow involved in the regulation of glucose transport. The new research indicates that insulin regulates Myo1c function via CaMKII-dependent phosphorylation, which plays a role in insulin-regulated trafficking of glucose transporter proteins (GLUT4) to the plasma membrane in adipocytes, according to Freddy Yip, the investigator on this research.
Insulin usually moves glucose transporter proteins from inside the cell to the surface membrane so that they can pump glucose into the cell. Myo1c aids in this process by helping the transporters slide into the surface membrane. In healthy people, around 80% of the glucose transporters migrate to the cell membrane after a meal, allowing plenty of glucose into the cell. In people with Type 2 diabetes, however, that figure drops to around 10%, according to Yip.
“We think there may be blockages in the signal between insulin and Myo1c in people who develop insulin resistance,” explains Yip.
The paper is published online on November 5 in Cell Metabolism.