Track topics on Twitter Track topics that are important to you
Membrane targeting proteins are recruited to specific membranes during cell signaling events, including signals at the leading edge of chemotaxing cells. Recognition and binding to specific lipids play a central role in targeting reactions, but it remains difficult to analyze the molecular features of such protein-lipid interactions. We propose that the surface diffusion constant of peripheral membrane-bound proteins contains useful information about protein-lipid contacts and membrane dynamics. To test this hypothesis, we use single-molecule fluorescence microscopy to probe the effects of lipid binding stoichiometry on the diffusion constants of engineered proteins containing one to three pleckstrin homology domains coupled by flexible linkers. Within error, the lateral diffusion constants of these engineered constructs are inversely proportional to the number of tightly bound phosphatidylinositol-(3,4,5)-trisphosphate lipids. The same trend is observed in coarse-grained molecular dynamics simulations and hydrodynamic bead calculations of lipid multimers connected by model tethers. Overall, single molecule diffusion measurements are found to provide molecular information about protein-lipid interactions. Moreover, the experimental and computational results independently indicate that the frictional contributions of multiple, coupled but well-separated lipids are additive, analogous to the free-draining limit for isotropic fluids-an insight with significant implications for theoretical description of bilayer lipid dynamics.
Molecular Biophysics Program and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado.
This article was published in the following journal.
Name: Biophysical journal
The cytoskeleton underlying cell membranes may influence the dynamic organization of proteins and lipids within the bilayer by immobilizing certain transmembrane (TM) proteins and forming corrals with...
The important process of nutrient uptake in Escherichia coli, in many cases, involves transit of the nutrient through a class of beta-barrel proteins in the outer membrane known as TonB-dependent tran...
What are the physical laws of the diffusive search of proteins for their specific binding sites on DNA in the presence of the macromolecular crowding in cells? We performed extensive computer simulati...
Single-molecule FRET measurements have a unique sensitivity to protein conformational dynamics. The FRET signals can either be interpreted quantitatively to provide estimates of absolute distance in a...
Dimerization of membrane protein interfaces occurs during membrane protein folding and cell receptor signaling. Here, we summarize a method that allows for measurement of equilibrium dimerization reac...
This study aims to demonstrate equivalence in terms of molecule removal between continuous hemodialysis using an "enhanced middle molecule clearance" membrane(Ultraflux EMiC2) and continuo...
Subjects who eventually undergo treatment for HCV, we will gather treatment data (start and stop dates), and repeat CB-CAP analysis at weeks 4, 12, 24 and 72 (+/- 2 week window allowed at ...
The emergence of hepatocellular carcinoma (HCC) has prompted a search for a thorough understanding of the biology of one of its major causative agents, the hepatitis B virus (HBV). HBV par...
The emergence of hepatocellular carcinoma (HCC) has prompted a search for a thorough understanding of the biology of one of its major causative agents, the hepatitis C virus (HCV). HCV par...
This is a single-arm, single-institution pilot study that will collect preliminary data to be used in the design of a subsequent study to assess whether changes in fDM (Functional Diffusio...
Surgical reconstruction of the hearing mechanism of the middle ear, with restoration of the drum membrane to protect the round window from sound pressure, and establishment of ossicular continuity between the tympanic membrane and the oval window. (Dorland, 28th ed.)
A method used to study the lateral movement of MEMBRANE PROTEINS and LIPIDS. A small area of a cell membrane is bleached by laser light and the amount of time necessary for unbleached fluorescent marker-tagged proteins to diffuse back into the bleached site is a measurement of the cell membrane's fluidity. The diffusion coefficient of a protein or lipid in the membrane can be calculated from the data. (From Segen, Current Med Talk, 1995).
A family of monosaccharide transport proteins characterized by 12 membrane spanning helices. They facilitate passive diffusion of GLUCOSE across the CELL MEMBRANE.
Type C cytochromes that are small (12-14 kD) single-heme proteins. They function as mobile electron carriers between membrane-bound enzymes in photosynthetic BACTERIA.
Surgical construction of an opening or window in the pericardium. It is often called subxiphoid pericardial window technique.
Within medicine, nutrition (the study of food and the effect of its components on the body) has many different roles. Appropriate nutrition can help prevent certain diseases, or treat others. In critically ill patients, artificial feeding by tubes need t...