Researchers at Washington University School of Medicine in St. Louis have made a discovery that could help scientists find better treatments for type 2 diabetes, obesity and other health problems caused by the body’s inability to properly regulate blood sugar.
The group identified a potent regulator of sensitivity to insulin, the hormone that controls blood sugar levels.
Fat and muscle cells in patients with type 2 diabetes become resistant to insulin, which normally causes them to take in glucose from the blood. Researchers found that a protein known as TBC1D3 — found only in humans and certain primates — keeps the insulin pathway open, so the cells can continue to take up glucose.
“When cells made more of the TBC1D3 protein, they had a much bigger response to insulin,” said senior author Philip Stahl, PhD, professor of cell biology and physiology. “We found that TBC1D3 significantly slows the deactivation of a molecule that relays signals from the insulin receptor. This enhances the cells’ response to insulin.”
“We found that TBC1D3 activates a protein called PP2A,” he continued in a press release. “Flies had shorter lifespans when the PP2A gene was knocked out. This suggests that TBC1D3 also may influence the aging process.”
Researchers are now investigating the factors that regulate the activity of TBC1D3, one of which may be the number of copies of the TBC1D3 gene in a person’s DNA.
Since TBC1D3 is one of the most duplicated genes in humans, appearing anywhere from five to more than 50 times in an our DNA, the team of scientists plans to compare cells with many copies of the gene to those with fewer copies to see whether the number of copies influences changes in the cells’ response to insulin.