Study of the effect of rapamycin on mTOR complex using capillary isoelectric focusing coupled with laser induced fluorescence-detector

Decreased muscle function due to loss of muscle mass is observed in conditions like obesity, hyperlipidemia, hypercholesterolemia, diabetes. Such a decrease in muscle mass is attributed to imbalance between protein synthesis and degradation primarily caused by hyperactive protein- kinase called mammalian target of rapamycin (mTOR). mTOR is a key protein in the hormone sensitive signaling pathway that regulates cell growth. mTOR exists as a part of complex with other protein subunits. mTOR attached to a protein subunit, raptor is mTOR1 and mTOR attached to a protein subunit rictor is mTOR 2. Its hyperactivity is predominantly observed in obese skeletal muscle. Hyper active mTOR signaling in obese skeletal muscle is normalized by using rapamycin. Besides its inhibition of mtor1, rapamycin has many side effects, like hair loss (alopecia) and nail disorders, loss of testicular function, hyperlipidemia, and decreased insulin sensitivity. All these side effects of rapamycin make it an undesirable drug of choice for normalizing hyperactive mTOR. Hence recent focus has been shifted towards the development of rapalogs (mimics of rapamycin) that have the same mechanism of action of rapamycin (mTOR activity inhibition) but with minimum side effects. Better understanding the behavior of mTOR complex in the presence and absence of rapamycin aids in development of rapalogs. Our main goal is to develop preliminary conditions using capillary isoelectric focusing to study mTOR inhibition by rapamycin in its native (intact) form.