Adenovirus-mediated silencing of Synaptotagmin 9 inhibits Ca2+-dependent insulin secretion in islets

• Synaptotagmins (Syts) are involved in Ca2+-dependent insulin release. However, which Syt isoform is functional in primary beta-cells remains unknown. We demonstrate by electron microscopy of pancreatic islets, the association of Syt 9 with insulin granules. Silencing of Syt 9 by RNA interference adenovirus in islet cells had no effect on the expression of Syt 5, Syt 7 and Syt 3 isoforms. The latter was localized at the plasma membrane of pancreatic polypeptide cells. Insulin release in response to glucose or tolbutamide was strongly inhibited in Syt 9 deficient islets, whereas exocytosis potentiated by raising cAMP levels, was unaltered. Thus, Syt 9 may act as Ca2+ sensor for beta-cell secretion.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

insulin exocytosis

pancreatic islets

electron

RNA

microscopy

interference

beta-cell

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)