Abstract

Cholesterol loading in macrophages stimulates formation of ER-derived vesicles with elevated ACAT1 activity

Highlights

  • ACAT1 is normally a resident enzyme in the endoplasmic reticulum (ER)

  • Likewise, when primary human macrophages grown in medium A were treated with aggregated LDL, cellular cholesterol content increased from 10.4 to 34.1 μg/mg protein; cholesteryl ester content increased from 5.1 to 148 μg/mg protein (Fig. 1A, right panels)

  • The results showed that in basal “medium A” conditions, most of the ACAT1 signal appeared in the medium-density fractions where the ER marker protein calnexin and the trans-Golgi network (TGN) marker protein syntaxin 6 were found (Fig. 2A)

Read more

Summary

Introduction

ACAT1 is normally a resident enzyme in the endoplasmic reticulum (ER). We previously showed that treating macrophages with denatured LDL causes a large increase in ER-derived, ACAT1-positive vesicles. In human macrophages, when maintained in normal medium, the ACAT1 signal is mainly with the tubular ER; adding modified LDL to the growth medium of these cells caused up to 30–40% of the total ACAT1 immunoreactive signals to become associated with small, ER-derived vesicles 80–100 nm in diameter [13]. These studies suggest that in macrophages, ACAT1 can be associated with ER-derived vesicles, especially when cells are grown in cholesterol-rich conditions. Journal of Lipid Research Volume 51, 2010 1263 positive membrane fractions and evaluated the ACAT enzyme activities in these fractions

Methods
Results
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.