Fig. 2

The four CPEBs form cytoplasmic foci that possess distinct biophysical properties. A U-2 OS cells overexpressing either full-length or NTD CPEB1-4-GFP fusions. Scale bar, 10 μm. B Left: percentage of cells displaying “focal,” in blue, versus “diffuse,” in orange, cytoplasmic distribution of full length (FL) CPEB1-4 (1, 2, 3, 4), the latter defined by the absence of foci. Right: fold change (FC) increase in the number of “diffuse” cells in the N-terminal domain (NTD) constructs relative to full length (FL). CPEB1, n = 67; CPEB2, n = 72; CPEB3, n = 65; CPEB4, n = 67; CPEB1-NTD, n = 65; CPEB2-NTD, n = 65; CPEB3-NTD, n = 59; CPEB4-NTD, n = 63. C Quantification of CPEB1-4-GFP cytoplasmic foci features: sphericity, volume and number, and ratio soluble-to-total fluorescence intensity. n as specified for B. D The mean fluorescence recovery upon photobleaching (FRAP) curves of CPEB1-4-GFP. E Distribution of the half-time of recovery (t-half) and recovery fraction parameters obtained from the FRAP curves. CPEB1, n = 82; CPEB2, n = 95; CPEB3, n = 106; CPEB4, n = 109. F U-2 OS cells overexpressing either wt or phosphomimetic CPEB1-4-GFP fusions. Scale bar, 10 μm. G Fraction of cells displaying “focal,” in blue, versus “diffuse,” in orange, cytoplasmic distribution in wt versus phosphomimetic mutants. CPEB1 wt, n = 72; CPEB1-DE (6D-DD), n = 71; CPEB2 wt, n = 74; CPEB2-DE (20 DE), n = 83; CPEB3 wt, n = 65; CPEB3-DE (18 DE), n = 68; CPEB4 wt, n = 73; CPEB4-DE (12 DE), n = 72. In C and E, comparisons between the groups were carried out using the Kruskal–Wallis test (significance level 5%) and post hoc Dunn’s test with Holm’s correction. Significance scale: ****P-adj < 0.0001; ***P-adj < 0.001; **P-adj < 0.01; *P-adj < 0.05, non-significant differences not indicated. Abbreviations: FL, full-length; NTD: N-terminal domain; wt, wild-type; DE, phosphomimetic mutant