Lipid Droplets in Disease

Lipid droplets (LDs) are a crucial part of lipid storage; thus, they are important players in a variety of diseases that are affected by lipid imbalances such as obesity, fatty liver disease, type 2 diabetes, Alzheimer’s disease, cardiovascular disease, and cancer [...

Coarse-grained cytoskeleton and filament simulations and mimicry with polymer worm micelles

Mimicry of cellular components is a logical starting point for creating sophisticated materials and also aids in the understanding of the model biological machinery. This thesis explores the mimicry of cytoskeletal biopolymers with giant worm micelles. In particular, the bending rigidity of the worm micelles can be chemically tuned to match the rigidity of intermediate filaments to microtubules. It is also shown here that the exterior of the worm micelles can be chemically modified with small ligands and peptides that bind specifically to cell membrane receptors. Preceding the design and work on these worm micelles, statistical mechanical approaches were used to elaborate the general phase behavior and surface interaction properties of cytoskeletal biopolymers. In the end, the worm micelles were incorporated back into a biological environment as drug delivery vehicles

Molecular Dynamics Simulations of Arp2/3 Complex Activation

Actin-related protein 2 and 3 (Arp2/3) complex forms a dendritic network of actin filaments during endocytosis and cellular locomotion by nucleating branches on the sides of preexisting actin filaments. Reconstructions of electron tomograms of branch junctions show how Arp2/3 complex anchors the branch, with Arp2 and Arp3 serving as the first two subunits of the branch. Our aim was to characterize the massive conformational change that moves Arp2 ∼30 Å from its position in crystal structures of inactive Arp2/3 complex to its position in branch junctions. Starting with the inactive crystal structure, we used atomistic-scale molecular dynamics simulations to drive Arp2 toward the position observed in branch junctions. When we applied forces to Arp2 while restraining Arp3, one block of structure (Arp2, subunit ARPC1, the globular domain of ARPC4 and ARPC5) rotated counterclockwise by 30° around a pivot point in an α-helix of ARPC4 (Glu81-Asn100) to align Arp2 next to Arp3 in a second block of structure including ARPC3 and the globular domains of ARPC2. This active structure buried more surface area than the inactive conformation. The complex was stable in all simulations. In most simulations, collisions of subdomain 2 of Arp2 with Arp3 impeded the movement of Arp2

Tetra-Primer Amplification-Refractory Mutation System (ARMS)—PCR for Genotyping Mouse Leptin Gene Mutation

Due to spontaneous deficiency in leptin, ob/ob mice are one of the most commonly used experimental animal models in diabetes research. In this study, we reported a quick and easy-to-conduct genotyping method using tetra-primer amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) to differentiate mice with a mutated allele from the wild-type genotype. The amplicon patterns of different genotypes are clearly visible and distinguishable on 1.5% agarose gel. This method can serve as a valuable tool to differentiate genotypes for breeding purposes, to maintain animal colonies, control the available space in the animal facility, and identify appropriate individuals for animal experiments