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. 2022 Nov 8;23(22):13667. doi: 10.3390/ijms232213667

Figure 2.

Figure 2

Regulation of cholesterol biosynthesis. SREBP-2 is the main regulator of cholesterol biosynthesis and is responsible for increases in blood cholesterol; it is attached to the ER membrane through its interaction with SCAP and INSIG1. When cholesterol levels decrease, INSIG1 is degraded, and the remaining SREBP-2–SCAP complex is inserted into the COPII vesicle in a process driven by GTPase and with the help of a protein complex consisting of Sar1 and Sec23–25. The SREBP-2–SCAP complex is transported to the Golgi by the COPII vesicle, where it is degraded by proteases S1P and S2P. This causes the release of the active domain of SREBP-2, which is transferred to the nucleus and binds to the SRE, resulting in the transcription of genes involved in cholesterol synthesis: HMGCR, HMG-CoA synthase, and MVK, as well as LDLR, which is responsible for cholesterol uptake. (Created with BioRender.com (accessed on 1 September 2022)).