circadian cycling of vesicle transport / fusion

In a very nice study by Panda et al., Cell 109: 307-320, 2002, the authors show cycling of just about everything in the SCN. Specifically, vesicle transport and fusion proteins Munc and SNAP cycle dusk / dawn.

"Several components involved in vesicle trafficking are circadianly regulated to two distinct phases. AP4-sigma, involved in trans-golgi cycling (Hirst et al., 1999); synapsin 1, implicated in maintenance of a release-ready pool of presynaptic vesicles (Li et al., 1995); and Vps29, involved in recycling components from the endosome to the trans-golgi (Seaman et al., 1997), all cycle in phase with Sgne1 and somatostatin. In contrast, Snap25 and Munc18c(Jahn, 2000), which mediate vesicle fusion; Eps15, implicated in vesicle recycling (Salcini et al., 2001); and Vps4b, involved in late endosomal vesicle transport (Yoshimori et al., 2000), cycle with a peak in the late subjective day, CT10."

This should have implcations on intra-SCN synapses...and data showing changes in synaptic strength might be expected to be taken more seriously (not that I'm bitter...)