Will Deaver, M.S.
The DEP domain containing mTOR-interacting protein, or DEPTOR, is a relatively new protein that our lab has focused on for its potential roles in muscle physiology. DEPTOR is a negative regulator of mTOR, a keystone protein responsible for muscle protein synthesis and cell growth. Essentially, mTOR signals for muscle growth. DEPTOR is a negative inhibitor of mTOR, and high levels of DEPTOR prevent mTOR signaling and result in lower muscle masses.
Recently, our lab published an article in FASEB Journal on one of the first projects to study DEPTOR in muscle. In the study, obese Zucker rats were utilized to simulate insulin-resistant, Type II Diabetic patients. The obese Zucker rat experiences a lot of the same symptoms as a Type II diabetic: high blood glucose, low insulin, high triglycerides, and low muscle mass despite higher overall weights (smaller muscles with obesity). Lean littermates do not exhibit any of these health issues and were used to represent the healthy population as a control.
Animals were taught to perform resistance exercise, and the study looked at the immediate results of weight training on muscle outcomes. While not a long-term training study, our lab looked at the immediate effects of lifting in the diabetic condition.
It was found that the severely obese animals showed very high levels of protein creation, but simultaneously showed signs of muscle wasting, indicating that protein turnover rates were also elevated.
However, the most interesting finding of the study was that DEPTOR was significantly suppressed in the skeletal muscle of the obese rats. It seems probable that if DEPTOR levels could be returned to a normal state, that mTOR activation would follow suit. If mTOR signaling were returned to normal, then it is possible that insulin sensitivity could be improved. DEPTOR and mTOR signaling could prove to be a critical target in the treatment and management of type II diabetes. Some 25.8 million Americans are afflicted by this disease, and DEPTOR regulation has the potential to be the answer that they have been looking for.