When the presynaptic membrane protein syntaxin is coexpressed in Xenopus oocytes with N- or P/Q-type Ca(2+) channels, it promotes their inactivation (Bezprozvanny et al., 1995; Wiser et al., 1996, 1999; Degtiar et al., 2000) (I. B. Bezprozvanny, P. Zhong, R. H. Scheller, and R. W. Tsien, unpublished observations). These findings led to the hypothesis that syntaxin influences Ca(2+) channel func...

is normally a random coincidence, and need not concern us a lot. If, however, similarities mount up, and we find several, perhaps even many, similarities between two separate things, matters start to change. We will start to wonder whether the two things might not actually somehow be related. Such a relationship might be functional, as in the case of axes or hammers, which are similar all over ...