FIGURE 6.

Subcellular distribution and secretagogue-stimulated release of the N- and C-terminal half-domains of SgII in PC12 cells. A, three-dimensional reconstruction of the subcellular distribution of SIG-SgII-GFP, SIG-SgII-(1-301)-GFP, and SIG-SgII-(302-587)-GFP expressed in PC12 cells. B, secretagogue-evoked secretion of SgII domain-EAP chimeras. PC12 cells expressing SIG-EAP, SIG-SgII-EAP, SIG-SgII-(1-301)-EAP, or SIG-SgII-(302-587)-EAP were exposed for 15 min to secretion medium alone (mock) or to 2 mm Ba²⁺. The enzymatic activity of EAP chimeras was assayed in the culture supernatant and cell lysate, and relative secretion was determined as described in the legend of Fig. 4. Values are given as the means ± S.E. of triplicate determinations. †, p > 0.05; ^**, p < 0.01; ^***, p < 0.001, as compared with control (mock), ANOVA with Dunnett's post test. Scale bar, 5 μm.