Regulated exocytosis: a novel, widely expressed system.
Electrophysiological studies in some secretory and non-secretory cells have identified an extensive form of calcium-induced exocytosis that is rapid (hundreds of milliseconds), insensitive to tetanus toxin and distinct from regulated secretion. We have now identified a marker of the process, desmoyokin-AHNAK, in a clonal derivative of the neuronal cell line, PC12. In resting cells, desmoyokin-AHNAK is localized within the lumen of specific vesicles, but appears on the cell surface during stimulation. Desmoyokin-AHNAK-positive vesicles exist in a variety of cells and tissues and are distinct from the endoplasmic reticulum, Golgi, trans-Golgi, endosomes and lysosomes, and from Glut4 and constitutive secretion vesicles. They seem to be involved in two models of plasmalemma enlargement: differentiation and membrane repair. We therefore propose that these vesicles should be called 'enlargosomes'.
Borgonovo
Barbara
B
Department of Neuroscience, Vita-Salute San Raffaele University and Excellence Centre in Cell Differentiation, via Olgettina 58, 20132 Milan, Italy.
Cocucci
Emanuele
E
Racchetti
Gabriella
G
Podini
Paola
P
Bachi
Angela
A
Meldolesi
Jacopo
J
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000502:physiology; D003594:Cytoplasmic Granules / Q000502:physiology* / Q000648:ultrastructure; D005089:Exocytosis / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology*; D009363:Neoplasm Proteins / Q000502:physiology*; D016716:PC12 Cells; D051381:Rats
C489573:Ahnak protein, rat; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D002118:Calcium