Fig. 8. (A) Detection of a MAP kinase isoform and tubulin in protein extracts from Ciona intestinalis. Coomassie Blue-stained gel showing the total proteins from Ciona intestinalis before (18 hpf) and after (24 hpf) induction of metamorphosis (upper panel; lanes 1 and 2, respectively). Corresponding western immunoblots probed with the anti-ERK1/ERK2, anti-activated ERK1/ERK2 and anti-tubulin antibodies (lower panels). Western immunoblot analysis shows the presence of equivalent amount of a MAP kinase isoform in both Ciona intestinalis extracts, whereas activation of this MAP kinase is detected only after metamorphosis induction. 
-Tubulin breakdown is also observed at this stage. C2 C12 cells were used as control (lane 3). (B) Alignment of Ciona and human -tubulin. Ciona -tubulin (Ci -tub) was aligned with human -tubulin (Hs -tub, NP_006073). Conserved residues are indicated by a dash. Non-conserved residues are shaded. (C) Alignment of Ciona ERK and p38 with MAPK from other species. Ciona sequences were aligned with ERK2 from frog (XlERK2, CAA42482.1), human (HsERK2, NP_002736.1), mouse (MmERK2, NP_036079.1) and fish (DrERK2, BAB11813.1), with ERK1 from human (HsERK1, AAH13992.1) and mouse (MmERK1, S28184), and with p38 from human (Hsp38, Q16539) and frog (Xlp38, P47812). Red indicates residues shared by all proteins; blue indicates residues shared by all ERKs; gray indicates consensus p38 residues; yellow indicates specific ERK1 residues; green indicates residues shared by ERK1 and CiERK2; the blue shading indicates epitope recognized by the ERK monoclonal anti-phosphotyrosine antibody.
