Both alter intracellular calcium homeostasis (Elferink 1999; Hare et al. 1993; Kang et al. 2006; Limke et al. 2004b; Machaty et al. 1999; Marty and Atchison 1997; Minnema et al. 1987; Peng et al. 2002; Sayers et al. 1993; Sirois and Atchison, 2000; Szalai et al. 1999; Tornquist et al. 1999; Zarini et al. 2006).