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  • Calcium dependencies of regulated exocytosis in different endocrine cells
    Dolenšek, Jurij ; Skelin, Maša ; Rupnik, Marjan
    Exocytotic machinery in neuronal and endocrine tissues is sensitive to changesin intracellular Ca2+ concentration. Endocrine cell models, that are most frequently used to study the mechanisms of ... regulated exocytosis, are pancreatic beta cells, adrenal chromaffin cells and pituitary cells. To reliably study the Ca2+ sensitivity in endocrine cells, accurate and fast determination of Ca2+ dependence in each tested cell is required. With slow photo-release it is possible to induce ramp-like increase in intracellular Ca2+ concentration ([Ca2+]i) that leads to a robust exocytotic activity. Slow increases in the [Ca2+]i revealed exocytotic phases with different Ca2+ sensitivities that have been largely masked in step-like flash photo-release experiments. Strikingly, in the cells of the three described model endocrine tissues (beta, chromaffin and melanotroph cells), distinct Ca2+ sensitivity ćclassesć of secretory vesicles have been observed: a highly Ca2+-sensitive, amedium Ca2+-sensitive and a low Ca2+- sensitive kinetic phase of secretory vesicle exocytosis. We discuss that a physiological modulation of a cellular activity, e.g. by activating cAMP/PKA transduction pathway, can switch the secretory vesicles between Ca2+ sensitivity classes. This significantly alterslate steps in the secretory release of hormones even without utilizationof an additional Ca2+ sensor protein.
    Vir: Physiological research. - ISSN 0862-8408 (Vol. 60, iss. Suppl. 1, 2011, str. S29-S38)
    Vrsta gradiva - članek, sestavni del ; neleposlovje za odrasle
    Leto - 2011
    Jezik - angleški
    COBISS.SI-ID - 512147512

vir: Physiological research. - ISSN 0862-8408 (Vol. 60, iss. Suppl. 1, 2011, str. S29-S38)

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