SYNAPSE ACTIVITY: PICCOLO COULD HAVE TWO
DIFFERENT ROLES
Piccolo, the pre-synaptic
protein known for its involvement in the assembly of the active zone, exists in
two variants, which properties are under investigation. A new structural study
(J.
Garcia et al. A conformational switch in the Piccolo C2A domain
regulated by alternative splicing. Nature Struct. Mol. Biol. 11, 45-53,
2004)
reported that C2A domain of Piccolo undergoes alternative splicing,
which yields isoforms that might have different roles.
A stretch of nine amino
acids in the C2A domain of Piccolo makes a structural difference
with synaptotagmin: this segment is alternatively spliced resulting either in a
short version of the protein or in a longer one. Splicing could constitute a
mechanism for the regulation of C2 domains, which are present in a
large number of proteins. Of course, to study the functional implications
related to the existence of these two isoforms, it will be necessary to indagate their effects
on the synaptic vesicle fusion.