A Trick of the Tail

Science Signaling  11 May 2010:
Vol. 3, Issue 121, pp. ec144
DOI: 10.1126/scisignal.3121ec144

The synaptic vesicle protein, synaptotagmin 1 (Syt1), acts as the main Ca2+-dependent switch for neurotransmitter release. In vitro studies of the truncated Syt1, which lacks the transmembrane domain, have unveiled the fusion-triggering mechanism of Syt1. However, in vitro approaches using the full-length, membrane-anchored Syt1 have not only failed to recapitulate Ca2+-triggered membrane fusion but could even inhibit vesicle fusion. In contrast, the membrane anchor is conserved across the Syt family, suggesting a critical functional role for the membrane anchor. Now, using a single-vesicle fusion assay, H.-K. Lee et al. show that the membrane anchor is indeed essential for Syt1 to induce physiological rates of Ca2+-induced vesicle fusion on a 100-millisecond time scale.

H.-K. Lee, Y. Yang, Z. Su, C. Hyeon, T.-S. Lee, H.-W. Lee, D.-H. Kweon, Y.-K. Shin, T.-Y. Yoon, Dynamic Ca2+-dependent stimulation of vesicle fusion by membrane-anchored synaptotagmin 1. Science 328, 760–763 (2010). [Abstract] [Full Text]