Browsing by Author "Erten, Nehir Birke"

Hypercholesterolemia is characterized by elevated levels of low-density lipoprotein (LDL) cholesterol in the bloodstream and contributes substantially to the global burden of atherosclerotic cardiovascular disease (ASCVD). Low-density lipoprotein receptor adaptor protein 1 (LDLRAP1) is an endocytic adaptor protein which assists LDL internalization by promoting LDLR localization in clathrin-coated pits and mutations in LDLRAP1 are associated with autosomal recessive hypercholesterolemia. However, the clinical relevance of many LDLRAP1 variants is yet to be fully determined. The aim of this master’s thesis is to adopt an analysis pipeline for bulk generation and functional characterization of such LDLRAP1 variants. To accomplish this goal, a cell model with impaired LDLR internalization is validated and the activity of LDLRAP1 and LDLRAP1 variants are evaluated within this system. This involves implementing a semi-automated variant generation pipeline to produce LDLRAP1 variants in large-scale, and LDLRAP1 variants are introduced into this cell system. The main finding of this thesis is that impaired LDLRAP1 function results in LDL-LDLR complexes to be retained on plasma membrane. The expression of LDLRAP1-GFP in internalization deficient cells reduced LDL and LDLR accumulation on plasma membrane. These features were evaluated for variant characterization, revealing three variants that may have impaired LDLRAP1 functionality. In conclusion, the findings of this thesis underscore the imperative for large-scale variant generation efforts and highlight the pivotal role of LDLRAP1 functionality in LDL internalization.