Age-dependent labeling and imaging of insulin secretory granules.
Insulin is stored within the secretory granules of pancreatic β-cells, and impairment of its release is the hallmark of type 2 diabetes. Preferential exocytosis of newly synthesized insulin suggests that granule aging is a key factor influencing insulin secretion. Here, we illustrate a technology that enables the study of granule aging in insulinoma cells and β-cells of knock-in mice through the conditional and unequivocal labeling of insulin fused to the SNAP tag. This approach, which overcomes the limits encountered with previous strategies based on radiolabeling or fluorescence timer proteins, allowed us to formally demonstrate the preferential release of newly synthesized insulin and reveal that the motility of cortical granules significantly changes over time. Exploitation of this approach may enable the identification of molecular signatures associated with granule aging and unravel possible alterations of granule turnover in diabetic β-cells. Furthermore, the method is of general interest for the study of membrane traffic and aging.
Molecular Diabetology, Paul Langerhans Institute Dresden, Dresden University of Technology, Dresden, Germany.
Anna
A
Ivanova
Yannis
Y
Kalaidzidis
Ronald
R
Dirkx
Mihail
M
Sarov
Michael
M
Gerlach
Britta
B
Schroth-Diez
Andreas
A
Müller
Yanmei
Y
Liu
Cordula
C
Andree
Bernard
B
Mulligan
Carla
C
Münster
Thomas
T
Kurth
Marc
M
Bickle
Stephan
S
Speier
Konstantinos
K
Anastassiadis
Michele
M
Solimena
D000818:Animals; D002460:Cell Line; D016922:Cellular Senescence / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism; D051379:Mice; D011384:Proinsulin / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism* / Q000502:physiology
D007328:Insulin; D011384:Proinsulin