Sensing of Cholesterol by Squalene Monooxygenase

Feedback regulation of squalene monooxygenase (SM), a rate-limiting enzyme of cholesterol synthesis, is an important component of cellular lipid homeostasis. This regulation is exerted in part by the cholesterol-induced degradation of the SM protein. Here, we describe the cell culture, sample preparation, and immunoblotting conditions that our laboratory routinely uses to study the cholesterol regulation of both endogenous and ectopic SM. We also provide a worked example of quantifying the cholesterol-induced degradation of SM using densitometry.