Biology subjects

Freeman, L. A.

Publications and source records attributed to Freeman, L. A..

2 recordsLinked to original sources

bioRxiv2020

Transgelin: A New Gene Involved in LDL Endocytosis Identified by a Genome-wide CRISPR-Cas9 Screen

To identify new genes involved in the cellular uptake of low-density lipoprotein (LDL), we applied a novel whole genome CRISPR/Cas9 knockout-screen on HepG2 cell lines. We identified TAGLN (transgelin), an actin-binding protein, as a new gene involved in LDL endocytosis. In silico validation demonstrated that genetically predicted differences in expression of TAGLN in human populations were associated with plasma lipids (triglycerides, total cholesterol, HDL, and LDL cholesterol) in the Global Lipids Genetics Consortium and lipid-related phenotypes in the UK Biobank. Decreased cellular LDL uptake observed in TAGLN-knockout cells due to decreased LDL receptor internalization, led to alterations in cellular cholesterol content and compensatory changes in cholesterol biosynthesis. Transgelin was also shown to be involved in the actin-dependent phase of clathrin-mediated endocytosis of other cargo besides LDL. The identification of novel genes involved in LDL uptake may improve the diagnosis of hypercholesterolemia and provide future therapeutic targets for the prevention of cardiovascular disease.

cell biology↗

bioRxiv2018

Molecular basis for activation of lecithin:cholesterol acyltransferase by a compound that increases HDL cholesterol

Lecithin:cholesterol acyltransferase (LCAT) and LCAT-activating small molecules are being investigated as treatments for coronary heart disease (CHD) and familial LCAT deficiency (FLD). Herein we report the crystal structure of LCAT bound to a potent activator and an acyl intermediate-like inhibitor, thereby revealing an active conformation of LCAT and that the activator is bound exclusively to its membrane-binding domain (MBD). Functional studies indicate that the compound does not modulate the affinity of LCAT for HDL, but instead stabilizes residues in the MBD and likely facilitates channeling of substrates into the active site. By demonstrating that these activators increase the activity of an FLD variant, we show that compounds targeting the MBD have therapeutic potential. In addition, our data better define the acyl binding site of LCAT and pave the way for rational design of LCAT agonists and improved biotherapeutics for augmenting or restoring reverse cholesterol transport in CHD and FLD patients.

biochemistry↗