Cellular compartment

About: Cellular compartment is a research topic. Over the lifetime, 1082 publications have been published within this topic receiving 53794 citations. The topic is also known as: cell compartmentation.

Mutation: Modified Starch Metabolism in Mutant and Transgenic Plants

Abstract: Unravelling the various steps in a metabolic pathway is a challenging task. The partitioning of metabolites and enzymes between different cellular compartments, such as mitochondria, plastids, vacuoles and endoplasmic reticulum, in eukaryotic cells, adds an additional level of complexity to the work. The use of mutants, and more recently also transgenic organisms, is often a very powerful approach to establish the correlation between a genetic locus and a metabolic activity and to elucidate the sequential steps in a metabolic pathway.

Post-translational processing of the murine third component of complement

Abstract: The biosynthesis and secretion of the third component of complement (C3) has been studied with the macrophage cell line J774.2. C3 is initially synthesized as a single polypeptide chain precursor termed pro-C3, of relative molecular weight (Mr) 170,000 that is post-translationally modified by proteolytic cleavage into two polypeptides linked by disulphide bonds. The larger polypeptide, termed the alpha chain, has an Mr of 110,000-115,000, while the smaller beta chain has an Mr of 55,000-60,000. Pulse-chase experiments indicate that the proteolytic processing of pro-C3 occurs intracellularly, just prior to secretion. Unlike human C3, which has carbohydrate on both the alpha and beta chains, only the alpha chain of murine C3 is glycosylated. The carboxylic ionophores monensin and nigericin totally inhibit the proteolytic processing of pro-C3 at a concentration of approximately 10(-6) M. This block on proteolytic processing was shown not to be mediated by changes in intracellular pH induced by the disruption of proton gradients. Rather, data from experiments using carboxylic ionophores and other perturbants of cellular physiology indicated that the enzyme(s) responsible for the proteolytic cleavage of pro-C3 either reside in a cellular compartment with a neutral pH or are proteinases active over a relatively broad pH range.

The shape of things to come: regulation of shape changes in endoplasmic reticulum.

Abstract: Shape changes in the endoplasmic reticulum control fundamental cell processes including nuclear envelope assembly in mitotic cells, calcium homeostasis in cytoplasmic domains of secreting and motile cells, and membrane traffic in the early secretion apparatus between the endoplasmic reticulum and Golgi. Opposing forces of assembly (membrane fusion) and disassembly (membrane fragmentation) ultimately determine the size and shape of this organelle. This review examines some of the regulatory mechanisms involved in these processes and how they occur at specific sites or subcompartments of the endoplasmic reticulum.

Regulation of Clara cell 10 kD protein secretion by pilocarpine: quantitative comparison of nonciliated cells in rat bronchi and bronchioles based on laser scanning confocal microscopy.

Abstract: Standard immunohistochemical techniques and laser scanning confocal microscopy were used to assess changes in the abundance of Clara cell 10 kD protein (CC10) within granules and endoplasmic reticulum of rat nonciliated cells after the administration of the secretagogue pilocarpine. Intracellular pools of CC10 were compared over time with time-matched controls at two airway levels, proximal bronchi and terminal bronchioles. Three zones of reflectance intensity (high, medium, and low), corresponding to different densities of CC10 were used to quantify changes in CC10 levels. We observed a shift in the abundance of CC10 from endoplasmic reticulum to granules 30 min after injection of pilocarpine. In addition, the depletion of granule-based CC10 occurred earlier in bronchial cells (30 min) than in bronchiolar cells (60 min). We also noted that the density of CC10 within the two cellular compartments remained steady even though the levels of CC10 dropped due to degranulation. Following degranulation, CC10 lev...