Which of the following proteins/enzymes is directly responsive to elevation in sterols, leading to a reduction in the transcriptional activation of the gene encoding HMG-CoA reductase?

Question

Quizplus · Accepted Answer

SCAP (SREBP cleavage-activating protein) senses sterol levels and regulates the activation of SREBP, which in turn affects the transcription of HMG-CoA reductase.  Sterols, particularly cholesterol, interact with SCAP and regulate the interaction of SCAP with the various SREBP proteins in the ER membrane. When sterols interact with SCAP, it results in SCAP retaining SREBP in the ER membrane such that it cannot migrate to the Golgi apparatus, where is would be acted upon by S1P. When sterol levels drop, the interaction between SCAP and SREBP is reduced and SREBP can migrate to the Golgi and be released from the membrane via the concerted actions of S1P and S2P.

Which of the Following Proteins/enzymes Is Directly Responsive to Elevation