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  • SNAP-25b-deficiency increases insulin secretion and changes spatiotemporal profile of Ca2+oscillations in [beta] cell networks [Elektronski vir]
    Daraio, Teresa ...
    SNAP-25 is a protein of the core SNARE complex mediating stimulus-dependent release of insulin from pancreatic [beta] cells. The protein exists as two alternatively spliced isoforms, SNAP-25a and ... SNAP-25b, differing in 9 out of 206 amino acids, yet their specific roles in pancreatic [beta] cells remain unclear. We explored the effect of SNAP-25b-deficiency on glucose-stimulated insulin release in islets and found increased secretion both in vivo and in vitro. However, slow photo-release of caged Ca2+ in [beta] cells within pancreatic slices showed no significant differences in Ca2+-sensitivity, amplitude or rate of exocytosis between SNAP-25b-deficient and wild-type littermates. Therefore, we next investigated if Ca2+ handling was affected in glucose-stimulated [beta] cells using intracellular Ca2+-imaging and found premature activation and delayed termination of [Ca2+] i elevations. These findings were accompanied by less synchronized Ca2+-oscillations and hence more segregated functional [beta] cell networks in SNAP-25b-deficient mice. Islet gross morphology and architecture were maintained in mutant mice, although sex specific compensatory changes were observed. Thus, our study proposes that SNAP-25b in pancreatic [beta] cells, except for participating in the core SNARE complex, is necessary for accurate regulation of Ca2+-dynamics.
    Source: Scientific reports [Elektronski vir]. - ISSN 2045-2322 (Vol. 7, 2017, 14 str.)
    Type of material - e-article
    Publish date - 2017
    Language - english
    COBISS.SI-ID - 512737080

    Link(s):

    http://www.nature.com/articles/s41598-017-08082-y
    Digital Library of the University of Maribor – DLUM
    DOI

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