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Univerzitetna knjižnica Maribor (UKM)
Knjižnica je med tednom odprta od 8. do 19. ure, ob sobotah od 9. do 13. ure. Čitalnica ČUK je odprta od ponedeljka do sobote od 9. do 24. ure, ob nedeljah od 16. do 24. ure. Informacije: 02 25 07 431, ukm@um.si
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  • Fusion-activated Ca2+ entry : an "active zone" of elevated Ca2+ during the postfusion stage of lamellar body exocytosis in rat type II pneumocytes
    Miklavc, Pika ...
    Background: Ca2+ is essential for vesicle fusion with the plasma membrane in virtually all types of regulated exocytoses. However, in contrast to the well-known effects of a high cytoplasmic Ca2+ ... concentration ([Ca2+]c) in the prefusion phase, the occurrence and significance of Ca2+ signals in the postfusion phase have not been described before. Methodology/Principal Findings: We studied isolated rat alveolar type II cells using previously developed imaging techniques. These cells release pulmonary surfactant, a complex of lipids and proteins, from secretory vesicles (lamellar bodies) in an exceptionally slow, Ca2+- and actin-dependent process. Measurements of fusion pore formation by darkfield scattered light intensity decrease or FM 1-43 fluorescence intensity increase were combined with analysis of [Ca2+]c byratiometric Fura-2 or Fluo-4 fluorescence measurements. We found that the majority of single lamellar body fusion events were followed by a transient (t1/2 of decay = 3.2 s) rise of localized [Ca2+]c originating at the site of lamellar body fusion. [Ca2+]c increase followed with a delay of ~0.2-0.5 s (method-dependent) and in the majority of cases this signal propagated throughout the cell (at ~10 m/s). Removal of Ca2+ from, or addition of Ni2+ to the extracellular solution, strongly inhibited these [Ca2+]c transients, whereas Ca2+ store depletion with thapsigargin had no effect. Actin-GFP fluorescence around fused LBs increased several seconds after the rise of [Ca2+]c. Both effects were reduced by the non-specific Ca2+ channel blocker SKF96365. Conclusions/Significance: Fusion-activated Ca2+ entry (FACE) is a new mechanism that leads to [Ca2+]c transients at the site of vesicle fusion. Substantial evidence from this and previous studies indicates that fusion-activated Ca2+ entry enhances localized surfactant release from type IIcells, but it may also play a role for compensatory endocytosis and other cellular functions.
    Vir: PloS one [Elektronski vir]. - ISSN 1932-6203 (Vol. 5, iss. 6, June 2010, str. 1-10)
    Vrsta gradiva - e-članek
    Leto - 2010
    Jezik - angleški
    COBISS.SI-ID - 65208577

    Povezava(-e):

    http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0010982
    DOI

vir: PloS one [Elektronski vir]. - ISSN 1932-6203 (Vol. 5, iss. 6, June 2010, str. 1-10)

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