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. 2005 Jan 14;102(4):1217–1221. doi: 10.1073/pnas.0409252102

Fig. 4.

Fig. 4.

Xenopus melanophores were seeded in six-well plates and kept in the dark for a minimum of 3 days. (A) IP3 determination in Xenopus melanophores in the dark and after a 15-min light exposure. Each bar is the mean ± SE (n = 3) percentage of the dark control, considered as 100%. Asterisks indicate a significant difference from the dark control. (B–D) Light-evoked melanosome dispersion in cells pretreated with 10–9 M melatonin for 90 min, in the absence (○) or presence of the PLC inhibitor, U-73122, at 5 × 10–6 M(▪) and 5 × 10–5 M(▴)(B); the Ca2+ chelator, BAPTA-AM, at 10–5 M(▪)(C); or the PKC inhibitor, Ro 31-8220, at 10–5M ▪)(D). The absorbance readings were expressed as the percentage of the absorbance of cells exposed to the EI50 for 60 min (considered as 100%). Each point is the mean ± SE (n = 6) at the times noted. Asterisks indicate a significant difference from the light response. (E) PKC activity in the dark and after a 15-min light exposure, in the absence or presence of the PKC inhibitor, Ro 31-8220, at 10–5 M. Each point is the mean ± SE (n = 6) phosphorylation rate in nmol/min. Asterisks indicate a significant difference from the dark control. (F) Representative Western blot of PKC-phosphorylated substrates in Xenopus melanophores maintained in the dark or after a 15-min light exposure or in the presence of 10–5 M phorbol 12,13-dibutyrate, in the absence or presence of the PKC inhibitor, Ro 31-8220, at 10–5 M. Lane 1, dark control; lane 2, light; lane 3, light plus 10–5 M Ro 31-8220; lane 4, 10–5 M phorbol ester; lane 5, 10–5 M phorbol ester plus 10–5 M Ro 31-8220.