Recycling of epidermal growth factor in A431 cells

AbstractThe fate of epidermal growth factor (EGF) after internalization by A431 cells was studied. First, cells containing 125I-EGF-receptor complexes in endosomes were obtained. Subsequent incubation of the cells at 37°C resulted in the recycling of 125I-EGF from endosomes to the cell surface in the receptor-bound state and the gradual release of recycled ligand into the medium. The excess of unlabeled EGF blocked both rebinding and re-internalization of recycled 125I-EGF to produce enhanced accumulation of ligand in the medium. The rate of recycling was shown to be much higher than that of EGF degradation

The Main Modernization Directions of the Industrial Complex

The functioning of enterprises in the conditions of economic uncertainty and high risks associated with it, dependence on external economic conjuncture, low competitiveness of domestic goods and services of Russia give determine a range of problems that can be solved only through modernization reforms in industry. They are determined by the formation of a competitive type of industrial production in Russia and high-tech industries that are able to generate high technology and modernize the sectoral system of national reproduction. Modernization of the Russian industry is based on internal growth factors using modern technologies and business methods with a gradual increase of the innovation potential. The purpose of the study is to identify the main directions of modernization for the formation of a modern competitive industry as the basis for ensuring economic growth and improving the quality of life of the population. To achieve this goal, the authors used dialectical, system-functional, economic-statistical, and formal-logical methods. In this contribution, the authors summarized the main directions of the implementation of industrial policy, presented statistical data on the creation of industrial parks. To strengthen the industrial potential of the Russian economy, it is necessary to provide conditions for the development of modern production, increasing production and energy efficiency, and increasing investment in fixed assets. The authors developed measures for the modernization of the industrial complex and predicted results of this program. Among key activities there are the development of affordable investment and innovation infrastructure, the creation of industrial parks and the development of the institutional environment

Selective and Signal-dependent Recruitment of Membrane Proteins to Secretory Granules Formed by Heterologously Expressed von Willebrand Factor

von Willebrand factor (vWF) is a large, multimeric protein secreted by endothelial cells and involved in hemostasis. When expressed in AtT-20 cells, vWF leads to the de novo formation of cigar-shaped organelles similar in appearance to the Weibel-Palade bodies of endothelial cells in which vWF is normally stored before regulated secretion. The membranes of this vWF-induced organelle, termed the pseudogranule, are uncharacterized. We have examined the ability of these pseudogranules, which we show are secretagogue responsive, to recruit membrane proteins. Coexpression experiments show that the Weibel-Palade body proteins P-selectin and CD63, as well as the secretory organelle membrane proteins vesicle-associated membrane protein-2 and synaptotagmin I are diverted away from the endogenous adrenocorticotropic hormone-containing secretory granules to the vWF-containing pseudogranules. However, transferrin receptor, lysosomal-associated membrane protein 1, and sialyl transferase are not recruited. The recruitment of P-selectin is dependent on a tyrosine-based motif within its cytoplasmic domain. Our data show that vWF pseudogranules specifically recruit a subset of membrane proteins, and that in a process explicitly driven by the pseudogranule content (i.e., vWF), the active recruitment of at least one component of the pseudogranule membrane (i.e., P-selectin) is dependent on residues of P-selectin that are cytosolic and therefore unable to directly interact with vWF