Journal of Cell Science 115, e1504-e1504 (2002)
© 2002 The Company of Biologists Limited
Regulation of PKC trafficking by synaptotagmin
Synaptotagmins play important roles in vesicle trafficking in neurons: they
act as fusion clamps during synaptic vesicle (SV) exocytosis and as receptors
for adaptor proteins during endocytosis of SV proteins. The proteins are also
expressed in other cell types, but we know very little about their roles in
non-neuronal cells. Ronit Sagi-Eisenberg and co-workers now reveal that
synaptotagmins are key regulators of protein kinase C (PKC) trafficking and
degradation in mast cells (see p.
3083). After prolonged exposure of mast cells to phorbol ester,
PKC
is transported to the plasma membrane and then to early/sorting
endosomes, where it is targeted for degradation. The authors observe that
overexpression of synaptotagmin II promotes PKC degradation in mast
cells, whereas transfection of antisense synaptotagmin II causes PKC to
be recycled. Using laser confocal microscopy and subcellular fractionation,
they demonstrate that, when synaptotagmin II levels are low, PKC is
diverted through recycling endosomes back to the plasma membrane.
Synaptotagmin II thus plays an active role in membrane trafficking in
non-neuronal cells and could thereby regulate cell signalling.
Related articles in JCS:
- Suppression of Synaptotagmin II restrains phorbolester-induced downregulation of protein kinase C by diverting the kinase from a degradative pathway to the recycling endocytic compartment
- Ze Peng, Elena Grimberg, and Ronit Sagi-Eisenberg
JCS 2002 115: 3083-3092.
[Abstract]
[Full Text]
