SNAP-23 functions in docking/fusion of granules at low Ca2+.
Chieregatti E, Chicka MC, Chapman ER, Baldini G, Mol Biol Cell, 2004 Apr - link

SNAP-25 and synaptotagmin 1 function in Ca2+-dependent reversible docking of granules to the plasma membrane.
Chieregatti E, Witkin JW, Baldini G, Traffic, 2002 Jul - link