The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Hanshermann Gerdes - One of the best experts on this subject based on the ideXlab platform.
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Partitioning and Exocytosis of Secretory Granules during Division of PC12 Cells
International journal of cell biology, 2012Co-Authors: Nickolay V. Bukoreshtliev, Erlend Hodneland, Tilo Wolf Eichler, Patricia Eifart, Amin Rustom, Hanshermann GerdesAbstract:The biogenesis, maturation, and exocytosis of Secretory Granules in interphase cells have been well documented, whereas the distribution and exocytosis of these hormone-storing organelles during cell division have received little attention. By combining ultrastructural analyses and time-lapse microscopy, we here show that, in dividing PC12 cells, the prominent peripheral localization of Secretory Granules is retained during prophase but clearly reduced during prometaphase, ending up with only few peripherally localized Secretory Granules in metaphase cells. During anaphase and telophase, Secretory Granules exhibited a pronounced movement towards the cell midzone and, evidently, their tracks colocalized with spindle microtubules. During cytokinesis, Secretory Granules were excluded from the midbody and accumulated at the bases of the intercellular bridge. Furthermore, by measuring exocytosis at the single granule level, we showed, that during all stages of cell division, Secretory Granules were competent for regulated exocytosis. In conclusion, our data shed new light on the complex molecular machinery of Secretory granule redistribution during cell division, which facilitates their release from the F-actin-rich cortex and active transport along spindle microtubules.
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Maturation of Secretory Granules.
Results and problems in cell differentiation, 2009Co-Authors: Tanja Kögel, Hanshermann GerdesAbstract:Exocrine, endocrine, and neuroendocrine cells store hormones and neuropeptides in Secretory Granules (SGs), which undergo regulated exocytosis in response to an appropriate stimulus. These cargo proteins are sorted at the trans-Golgi network into forming immature Secretory Granules (ISGs). ISGs undergo maturation while they are transported to and within the F-actin-rich cortex. This process includes homotypic fusion of ISGs, acidification of their lumen, processing, and aggregation of cargo proteins as well as removal of excess membrane and missorted cargo. The resulting mature Secretory Granules (MSGs) are stored in the F-actin-rich cell cortex, perhaps as segregated pools exhibiting specific responses to stimuli for regulated exocytosis. During the last decade our understanding of the maturation of ISGs advanced substantially. The use of biochemical approaches led to the identification of membrane molecules mechanistically involved in this process. Furthermore, live cell imaging in combination with fluorescently tagged marker proteins of SGs provided insights into the dynamics of maturing ISGs, and the functional implications of cytoskeletal elements and motor proteins.
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Myosin Va facilitates the distribution of Secretory Granules in the F-actin rich cortex of PC12 cells
Journal of Cell Science, 2003Co-Authors: Rudiger Rudolf, Tanja Kögel, Thorsten Salm, Andrea Hellwig, Sergei A. Kuznetsov, Oliver Schlicker, John A. Hammer, Hanshermann GerdesAbstract:Neuroendocrine Secretory Granules, the storage organelles for neuropeptides and hormones, are formed at the trans-Golgi network, stored inside the cell and exocytosed upon stimulation. Previously, we have reported that newly formed Secretory Granules of PC12 cells are transported in a microtubule-dependent manner from the trans-Golgi network to the F-actin-rich cell cortex, where they undergo short directed movements and exhibit a homogeneous distribution. Here we provide morphological and biochemical evidence that myosin Va is associated with Secretory Granules. Expression of a dominant-negative tail domain of myosin Va in PC12 cells led to an extensive clustering of Secretory Granules close to the cell periphery, a loss of their cortical restriction and a strong reduction in their motility in the actin cortex. Based on this data we propose a model that implies a dual transport system for Secretory Granules: after microtubule-dependent delivery to the cell periphery, Secretory Granules exhibit a myosin Va-dependent transport leading to their restriction and even dispersal in the F-actin-rich cortex of PC12 cells.
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dynamics of immature Secretory Granules role of cytoskeletal elements during transport cortical restriction and f actin dependent tethering
Molecular Biology of the Cell, 2001Co-Authors: Rudiger Rudolf, Amin Rustom, Thorsten Salm, Hanshermann GerdesAbstract:Secretory Granules store neuropeptides and hormones and exhibit regulated exocytosis upon appropriate cellular stimulation. They are generated in the trans-Golgi network as immature Secretory Granules, short-lived vesicular intermediates, which undergo a complex and poorly understood maturation process. Due to their short half-life and low abundance, real-time studies of immature Secretory Granules have not been previously possible. We describe here a pulse/chase-like system based on the expression of a human chromogranin B-GFP fusion protein in neuroendocrine PC12 cells, which permits direct visualization of the budding of immature Secretory Granules and their dynamics during maturation. Live cell imaging revealed that newly formed immature Secretory Granules are transported in a direct and microtubule-dependent manner within a few seconds to the cell periphery. Our data suggest that the cooperative action of microtubules and actin filaments restricts immature Secretory Granules to the F-actin-rich cell cortex, where they move randomly and mature completely within a few hours. During this maturation period, Secretory Granules segregate into pools of different motility. In a late phase of maturation, 60% of Secretory Granules were found to be immobile and about half of these underwent F-actin-dependent tethering.
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Signal-mediated sorting of chromogranins to Secretory Granules.
Advances in experimental medicine and biology, 2000Co-Authors: Hanshermann Gerdes, Michael M. GlombikAbstract:The proteins chromogranin A (CGA) and B (CGB) are constitutents of neuropeptideand hormone-containing Secretory Granules. As members of the granin protein family (Huttner et al., 1991) they represent widespread marker proteins for these organelles. CGA was the first discovered member of this family (Helle, 1966, Blaschko et al 1967, Smith and Winkler 1967), followed by secretogranin II (SgII) (Rosa and Zanini 1981, Zanini and Rosa 1981, Lee and Huttner 1983), a more distantly related protein, and CGB (Lee and Huttner 1983, Falkensammer et al 1985). In addition, other members of this family have been described (Huttner et al 199 1). Because of their abundance, widespread distribution in neuroendocrine tissues, and specific localization in Secretory Granules (Wiedenmann and Huttner 1989, Winkler and Fischer-Colbrie 1992, Rosa and Gerdes 1994) the granins have been used as prime candidates to study sorting to these organelles.
Regina Kuliawat - One of the best experts on this subject based on the ideXlab platform.
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lumenal protein multimerization in the distal Secretory pathway Secretory Granules
Current Opinion in Cell Biology, 2002Co-Authors: Peter Arvan, Bao Yan Zhang, Lijun Feng, Regina KuliawatAbstract:Differences in protein solubility appear to play an important role in lumenal protein trafficking through Golgi/post-Golgi compartments. Recent advances indicate that multimeric protein assembly is one of the factors regulating the efficiency of protein storage within Secretory Granules, by mechanisms that, with slight modification, might be considered to represent the culmination of a process of Golgi cisternal maturation.
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Lumenal protein multimerization in the distal Secretory pathway/Secretory Granules.
Current Opinion in Cell Biology, 2002Co-Authors: Peter Arvan, Bao Yan Zhang, Lijun Feng, Regina KuliawatAbstract:Differences in protein solubility appear to play an important role in lumenal protein trafficking through Golgi/post-Golgi compartments. Recent advances indicate that multimeric protein assembly is one of the factors regulating the efficiency of protein storage within Secretory Granules, by mechanisms that, with slight modification, might be considered to represent the culmination of a process of Golgi cisternal maturation.
Hiroshi Sugiya - One of the best experts on this subject based on the ideXlab platform.
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Involvement of AQP6 in the Mercury-Sensitive Osmotic Lysis of Rat Parotid Secretory Granules
The Journal of Membrane Biology, 2013Co-Authors: Miwako Matsuki-fukushima, J. Fujita-yoshigaki, Masataka Murakami, Osamu Katsumata-kato, Megumi Yokoyama, Hiroshi SugiyaAbstract:In Secretory Granules and vesicles, membrane transporters have been predicted to permeate water molecules, ions and/or small solutes to swell the Granules and promote membrane fusion. We have previously demonstrated that aquaporin-6 (AQP6), a water channel protein, which permeates anions, is localized in rat parotid Secretory Granules (Matsuki-Fukushima et al., Cell Tissue Res 332:73–80, 2008 ). Because the localization of AQP6 in other organs is restricted to cytosolic vesicles, the native function or functions of AQP6 in vivo has not been well determined. To characterize the channel property in granule membranes, the solute permeation-induced lysis of purified Secretory Granules is a useful marker. To analyze the role of AQP6 in Secretory granule membranes, we used Hg^2+, which is known to activate AQP6, and investigated the characteristics of solute permeability in rat parotid Secretory granule lysis induced by Hg^2+ (Hg lysis). The kinetics of osmotic Secretory granule lysis in an iso-osmotic KCl solution was monitored by the decay of optical density at 540 nm using a spectrophotometer. Osmotic Secretory granule lysis was markedly facilitated in the presence of 0.5–2.0 μM Hg^2+, concentrations that activate AQP6. The Hg lysis was completely blocked by β-mercaptoethanol which disrupts Hg^2+-binding, or by removal of chloride ions from the reaction medium. An anion channel blocker, DIDS, which does not affect AQP6, discriminated between DIDS-insensitive and sensitive components in Hg lysis. These results suggest that Hg lysis is required for anion permeability through the protein transporter. Hg lysis depended on anion conductance with a sequence of NO_3 ^− > Br^− > I^− > Cl^− and was facilitated by acidic pH. The anion selectivity for NO_3 ^− and the acidic pH sensitivity were similar to the channel properties of AQP6. Taken together, it is likely that AQP6 permeates halide group anions as a Hg^2+-sensitive anion channel in rat parotid Secretory Granules.
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Involvement of Aquaporin-5 Water Channel in Osmoregulation in Parotid Secretory Granules
The Journal of Membrane Biology, 2005Co-Authors: M. Matsuki, S. Hashimoto, M. Shimono, M. Murakami, J. Fujita-yoshigaki, S. Furuyama, Hiroshi SugiyaAbstract:Aquaporins (AQPs) are a family of channel proteins that allow water or very small solutes to pass, functioning in tissues where the rapid and regulated transport of fluid is necessary, such as the kidney, lung, and salivary glands. Aquaporin-5 (AQP5) has been demonstrated to localize on the luminal surface of the acinar cells of the salivary glands. In this paper, we investigated the expression and function of AQP5 in the Secretory Granules of the rat parotid gland. AQP5 was detected in the Secretory granule membranes by immunoblot analysis. The immunoelectron microscopy experiments confirmed that AQP5 was to be found in the Secretory granule membrane. Anti-AQP5 antibody evoked lysis of the Secretory Granules but anti-aquaporin-1 antibody did not and AQP1 was not detected in the Secretory granule membranes by immunoblot analysis. When chloride ions were removed from the solution prepared for suspending Secretory Granules, the granule lysis induced by anti-AQP5 antibody was inhibited. Furthermore, 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid, an anion channel blocker, blocked the anti-AQP5 antibody-induced Secretory granule lysis. These results suggest that AQP5 is, expressed in the parotid gland Secretory granule membrane and is involved in osmoregulation in the Secretory Granules.
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Translocation of Arf1 to the Secretory Granules in Rat Parotid Acinar Cells
Archives of biochemistry and biophysics, 1998Co-Authors: Yoko Dohke, Hiroshi Sugiya, J. Fujita-yoshigaki, Miki Hara-yokoyama, Richard A. Kahn, Yasunori Kanaho, Sadamitsu Hashimoto, Shunsuke FuruyamaAbstract:Abstract We investigated the interaction of ADP-ribosylation factor (Arf) with the Secretory Granules in rat parotid acinar cells. The 20.5-kDa small-molecular-mass GTP-binding protein in the cytosolic fraction of rat parotid acinar cells was identified as ADP-ribosylation factor1 by using a pan-Arf monoclonal antibody and isotype-specific polyclonal antibodies for Arf proteins 1, 3, 5, and 6. Incubation of the cytosolic fraction with isolated Secretory granule membranes in the presence of GTPγS resulted in the translocation of Arf1 from the cytosolic fraction to the Secretory granule membranes. The translocation was not observed in the presence of GDPβS in place of GTPγS, indicating that the process is GTP-dependent. The immunoelectron microscopy experiment confirmed Arf1 is translocated to the Secretory Granules. A prior treatment of the granule membranes with trypsin inhibited the translocation of Arf1 at 2 mM Mg 2+ , but had no effect in the absence of Mg 2+ (condition of spontaneous conversion of Arf-GDP to Arf-GTP). Thus, the trypsin-sensitive nucleotide exchange activity for Arf1 is probably associated with the Secretory granule membranes. These results demonstrate Arf1 translocates to the Secretory Granules in rat parotid acinar cells.
Ole H. Petersen - One of the best experts on this subject based on the ideXlab platform.
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Can Ca2+ be released from Secretory Granules or synaptic vesicles?
Trends in neurosciences, 1996Co-Authors: Ole H. PetersenAbstract:Recent studies on single isolated Secretory Granules, as well as Secretory Granules in intact cells, show that Ca2+ is released from the granule store into the cytosol via a messenger-mediated pathway following agonist binding. This is important for generation of localized cytosolic Ca2+ signals which can initiate exocytosis.
Wieland B. Huttner - One of the best experts on this subject based on the ideXlab platform.
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NeuroSecretory vesicles can be hybrids of synaptic vesicles and Secretory Granules
Proceedings of the National Academy of Sciences of the United States of America, 1995Co-Authors: Rudolf Bauerfeind, Ruth Jelinek, Andrea Hellwig, Wieland B. HuttnerAbstract:We have investigated the relationship of the so-called small dense core vesicle (SDCV), the major catecholamine-containing neuroSecretory vesicle of sympathetic neurons, to synaptic vesicles containing classic neurotransmitters and Secretory Granules containing neuropeptides. SDCVs contain membrane proteins characteristic of synaptic vesicles such as synaptophysin and synaptoporin. However, SDCVs also contain membrane proteins characteristic of certain Secretory Granules like the vesicular monoamine transporter and the membrane-bound form of dopamine beta-hydroxylase. In neurites of sympathetic neurons, synaptophysin and dopamine beta-hydroxylase are found in distinct vesicles, consistent with their transport from the trans-Golgi network to the site of SDCV formation in constitutive Secretory vesicles and Secretory Granules, respectively. Hence, SDCVs constitute a distinct type of neuroSecretory vesicle that is a hybrid of the synaptic vesicle and the Secretory granule membranes and that originates from the contribution of both the constitutive and the regulated pathway of protein secretion.
