2019_EJRNL_PP_Alberto_Ramperez-1.pdf
Terbatas Irwan Sofiyan
» ITB
Terbatas Irwan Sofiyan
» ITB
The cycling of synaptic vesicles ensures that neurons can communicate
adequately through their synapses on repeated occasions when activity is sustained,
and several steps in this cycle are modulated by actin. The effects of pharmacological
stabilization of actin with jasplakinolide or its depolymerization with latrunculin A was
assessed on the synaptic vesicle cycle at individual boutons of cerebellar granule cells,
using FM1-43 imaging to track vesicle recycling and its photoconversion to specifically
label recycled organelles. Remarkable differences in the recycling capacity of individual
boutons are evident, and their dependence on the actin cytoskeleton for recycling is
clear. Disrupting actin dynamics causes a loss of functional boutons, and while this
indicates that exo/endocytotic cycling in boutons is fully dependent on such events,
this dependence is only partial in other boutons. Indeed, exocytosis and vesicle
trafficking are impaired significantly by stabilizing or depolymerizing actin, whereas
repositioning recycled vesicles at the active zone seems to be dependent on actin
polymerization alone. These findings support the hypothesis that different steps of
synaptic vesicle cycling depend on actin dynamics and that such dependence varies among individual boutons.