Trafficking of molecules

Liu SH, Marks MS, Brodsky EM. A dominant-negative clathrin mutant differentially affects trafficking of molecules with distinct sorting motifs in the Class II major histocompatibihty complex (MHC) pathway. J Cell Biol 1998 140(5) 1023-1037. 

Abstract Tubulin is a fascinating molecule that forms the cytoskeleton of the cells and plays an important role in cell division and trafficking of molecules. It polymerizes and depolymerizes in order to fulfill this biological function. This function can be modulated by small molecules that interfere with the polymerization or the depolymerization. In this article, the structural basis of this behavior is reviewed with special attention to the contribution of NMR spectroscopy. Complex structures of small molecules that bind to tubulin and microtubules will be discussed. Many of them have been determined using NMR spectroscopy, which proves to be an important method in tubulin research. 

Altered trafficking of molecules through the endolysosomal network, including sequestration of membrane rafts, leading to a disruption in signaling... 

Often, experimental studies of lipid systems are based on spectroscopic approaches, which in turn frequently employ probes for enhancement of sensitivity and resolution. For example, in NMR, hydrogen atoms of lipids are replaced with deuterium, and in fluorescence spectroscopy and imaging, native lipid molecules are replaced with lipids in which one of the hydrocarbon chains is linked covalently to a fluorescent marker such as pyrene or diphenylhexatriene. Fluorescent markers allow one to follow numerous cellular processes in real time, such as intracellular trafficking of molecules and formation of domains within a biomembrane, see Fig. 3. The downside is that the probes tend to perturb their environment and affect the thermodynamic state of the system. Experiments have shown, for example, that probes may change the main transition temperature of a lipid membrane, and that the dynamics of probes may deviate considerably from the dynamics of corresponding native molecules (see discussion in Reference 27). Therefore, we wish to pose several questions. What is the range of perturbations induced by the probe How significant are these perturbations actually ... 

The HIV-1 coreceptors CXCR4 and CCR5 bind to ligand members of a family of molecules known as chemokines, or chemotactic cytokines. While the hallmark function of these small proteins is the direction of leukocyte trafficking, they can also participate in cellular events such as activation and costimulation (Bajetto et al. 2(X)la). Members of the chemokine family can be classified as either homeostatic or inflammatory based on their temporal expression (Charo and Ransohoff 2006 Kim 2005). Although traditionally the CNS had been thought to be protected from immune acti-... 

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