EMBO/SourceData huggingface dataset:
Figure 5B) Endogenous miR-16-5p activity in developing hippocampal neurons. Hippocampal neurons were transfected with 500ng miR16 or control sensor at 4 DIV and with or without LNA control ('LNA Ctrl') or the anti-sense miR-16-5p inhibitor ('LNA-miR16'). Cells were fixed at 7 DIV and the number of neurons expressing GFP and not dsRed ('GFP-only') was compared to the total number of transfected neurons. LNA-miR16 reduces the amount of repression of the miR16 sensor compared to LNA-Ctrl (n=4, p=0.02, t-test type 2, error bars represent s.d.).C) Short-term BDNF stimulation inhibits endogenous miR-16-5p activity. Hippocampal neurons were transfected at 4 DIV and treated with BDNF either 24h or 20 minutes before fixation and neurons were counted as in B. Repression index was obtained by normalizing the miR16 sensor to the control sensor condition in each experiment (n=4, p=0.02, t-test type 3, error bars; s.d.).D&E) Inhibition of miR-16-5p increases dendritic complexity and occludes BDNF-induced dendritogenesis. D) Hippocampal neurons were transfected with the control sensor (A), and stimulated with control or BDNF 24 hours before fixation. Pictures were obtained on a confocal microscope and thresholds were set to dsRed signal fluorescence in order to distinguish individual dendrites (scale bars are 10μm). E) To quantify dendritic complexity the total number of dendritic intersections was calculated using Sholl analysis. Values were normalized to LNA-Ctrl and control treatment (n=3, p<0.04, t-test type 3, error bars represent s.d.).F&G) Overexpression of miR-16-5p blocks BDNF-induced dendritogenesis. F) Hippocampal neurons were transfected with control sensor and either control miRNA mimic (miR-Ctrl) or a miR-16-5p mimic (miR16) and treated two days later with BDNF or control vehicle. DsRed signal fluorescence was used to set a threshold on images obtained on a confocal microscope (scale bars; 10μm). G) Total number of intersections was quantified in Sholl analysis and values were normalized to miR-Ctrl, control treatment in each experiment (n=4, p=0.02, t-test type 3, error bars; s.d.).H&I) Overexpression of the Dicer-binding deficient deletion mutant of TRBP (GFP-TRBP Δ) occludes BDNF-induced dendritogenesis. H) Hippocampal neurons were transfected with 200ng dsRed and either 50ng GFP or 200ng GFP-TRBP Δ, and treated two days later with BDNF or control vehicle. DsRed signal fluorescence was used to set a threshold on images obtained on a confocal microscope (scale bars; 10μm). I) Total number of intersections was quantified in Sholl analysis and values were normalized to control treatment in each experiment (n=5, p<0.02, t-test type 3, error bars; s.d.).
Figure 6B) MiR-16-5p targets the 3'UTR of the BDNFmRNA. Cortical neurons were transfected with 100ng pmiRGlo dual-luciferase reporter consisting of the 3'UTR of BDNF (3'UTR WT) or a miR-16-5p-binding site mutant (3'UTR Mut) and either miR-Ctrl or miR-16. The Firefly to Renilla luciferase ratio was measured and values were normalized to the respective reporter expression without miRNA mimic co-transfection (n=3, p=0.02, t-test type 2).C) BDNFstimulation leads to an increase in the translation of 3'UTR WT (p=0.02, t-test type 3) but not 3'UTR Mut luciferase reporter, which is rescued by miR-16-5p overexpression (p=0.002; t-test type 2). Cortical neurons were transfected as in (B), stimulated with BDNF or vehicle control for 20 minutes, and lysed two hours after stimulation (n=4).D) Pre-miR16 is present in the neuronal cell soma and processes of hippocampal neurons. Neurons were plated on compartmentalized chambers and RNA was isolated from the neuronal cell body and processes separately. Pre-miR137 and pre-miR341 were used to assay somatic and neurite enrichment, respectively. Raw Ct values were normalized to GAPDH mRNA in each experiment (n=3).
Figure 7More Dicer binds to membrane-targeted GFP-TRBP (mGFP-TRBP) compared to GFP-TRBP. HEK293T cells were transfected with GFP, GFP-TRBP or mGFP-TRBP and cell lysates were processed for co-IP using anti-GFP antibody. Dicer binding was normalized to respective input lanes in each condition (n=4, p=0.02; t-test type 2, error bars are s.d.).B) mGFP-TRBP but not GFP-TRBP blocks the BDNF-induced decrease in miR-16-5p activity in dual-fluorescence sensor assay. Hippocampal neurons were transfected with 200ng miR16- or control-sensor (see Fig 5A) plus 50ng GFP, 400ng GFP-TRBP or 400ng mGFP-TRBP. Neurons were treated with BDNF or vehicle control prior to fixation and immunostained with anti-GFP antibody. BDNF led to a decrease in miR-16-5p activity in GFP-transfected neurons (p=0.03, n=4, t-test type 3), which was significantly different from mGFP-TRBP-expressing neurons (p=0.04, n=4, t-test type 2, error bars are s.d.).C&D) BDNF-induced dendritogenesis is blocked by mGFP-TRBP overexpression. C) Hippocampal neurons (4DIV) were transfected for three days with 200ng dsRed and 50ng GFP, 400ng GFP-TRBP or 400ng mGFP-BDNF. Neurons were treated with BDNF or vehicle control 24 hours before fixation. Pictures were obtained on a confocal microscope and threshold was set for dsRed to distinguish individual dendrites (scale bars are 10μm). D) The total number of intersections was calculated in Sholl analysis, and values were normalized to control treatment in each of three independent experiments. BDNF led to a significant increase in dendritic complexity (p=0.04; t-test type 3), which was significantly different in cells transfected with mGFP-TRBP, but not GFP-TRBP (n=3, p=0.03; t-test type 2, error bars; s.d.).
Figure 1B-D Left ventricular LXRα expression in Wt and LXRα-Tg mice aged 12 weeks. (B) Western blot of LXRα in liver and LV tissue.B-D Left ventricular LXRα expression in Wt and LXRα-Tg mice aged 12 weeks. (B) Western blot of LXRα in liver and LV tissue. Quantification of (C) mRNA expression (normalized to 36b4; n = 6-8/group, *P < 0.00001 versus Wt) and (D) protein expression (normalized to GAPDH; n = 4/group, *P = 0.0001 versus Wt).E LV weight to tibia length ratios (LV/tibia); n = 15/group. *P = 0.02.F Assessment of mean arterial pressure (MAP) with in situ catheterization shows no significant differences.G Representative Masson's trichrome and wheat germ agglutinin (WGA)-FITC staining in cross-sectional LV, scale bars = 100 μm and 10 μm, respectively.H Relative mRNA levels of known LXRα-associated and target genes assessed with RT-PCR; n = 8/group. *P = 0.0003, #P = 0.0004, §P = 0.043, †P = 0.0009 versus Wt.
Figure 2LV/tibia ratios in sham- and TAC-operated Wt and LXRα-Tgmice; n = 21 Wt sham, n = 24 LXRα-Tg sham, n = 24 Wt TAC, n = 26 LXRα-TgTAC. *P < 0.00001 versus respective sham, #P = 0.00004.Quantification of cardiomyocyte cross-sectional area from WGA-FITC-stained histological sections; n = 5 Wt sham, n = 4 LXRα-Tg sham, n = 5 Wt TAC, n = 3 LXRα-TgTAC. **P = 0.00001 versus Wt sham, *P = 0.01 versus LXRα-Tg sham, #P = 0.01.Representative LV sections stained with WGA-FITC and Masson's trichrome to assess cardiomyocyte hypertrophy and fibrosis, respectively; scale bars = 1 mm, 100 μm, 10 μm, from top to bottom.Whole area percentage of fibrosis in Masson's trichrome-stained sections; n = 8 per group, except n = 7 in Wt TAC group. *P = 0.02 versus Wt sham, #P = 0.02.Measurement of mRNA levels with RT-PCR to assess induction of fetal gene program, as well as hypertrophy (Rcan1) and fibrosis (Col1a1, Ctgf); n = 8 per group, except n = 7 in Wt TAC group. Myh6/Myh7: *P = 0.0001 versus Wt sham, #P = 0.00001; Anp: *P = 0.0005 versus LXRα-Tg sham, #P = 0.02; Bnp: *P = 0.0006 versus Wt sham, **P = 0.009 versus LXRα-Tg sham, #P = 0.03; Acta1: §P < 0.00001 versus Wt sham, *P = 0.01 versus LXRα-Tg sham, #P = 0.001; Rcan1: **P = 0.00004 versus Wt sham, *P = 0.05 versus LXRα-Tg sham, #P = 0.04; Col1a1: *P = 0.00003 versus Wt sham; Ctgf: §P < 0.00001 versus Wt sham, #P = 0.00001.
Figure 3A Echocardiographic assessment of percent fractional shortening in mice subjected to 5 weeks of TAC; n = 19 Wt sham, n = 22 LXRα-Tg sham, n = 24 Wt TAC, n = 26 LXRα-TgTAC. **P < 0.00001 versus Wt sham, *P = 0.0005 versus LXRα-Tg sham, #P = 0.009.B-D Hemodynamic measurements obtained in situ in sham- and TAC-operated mice; n = 6-8/group. (B) Mean arterial pressure (MAP) showed no significant differences. (C) LV end-systolic pressure (LVESP). **P < 0.00001 versus Wt sham, *P = 0.00004 versus LXRα-Tg sham, *P = 0.003. (D) LV end-diastolic pressure (LVEDP). *P = 0.02 versus Wt sham.B-D Hemodynamic measurements obtained in situ in sham- and TAC-operated mice; n = 6-8/group. (B) Mean arterial pressure (MAP) showed no significant differences. (C) LV end-systolic pressure (LVESP). **P < 0.00001 versus Wt sham, *P = 0.00004 versus LXRα-Tg sham, *P = 0.003. (D) LV end-diastolic pressure (LVEDP). *P = 0.02 versus Wt sham.
Figure 4Representative 18F-FDG images with microPET in the coronal and axial planes in Wt and LXRα-Tg mice 5 weeks post-TAC.Myocardial FDG uptake measured as standard uptake value (SUV); n = 4-6/group. *P = 0.04 versus Wt sham, **P = 0.02 versus LXRα-Tg sham, #P = 0.03, ##P = 0.01.Quantification of myocardial glycogen content shows no significant differences; n = 5 per sham group, n = 7 per TAC group.GLUT protein expression in LV tissue normalized to GAPDH; n = 6/group. Glut1: *P = 0.01 versus LXRα-Tg sham, #P = 0.03; Glut4: *P = 0.03 versus LXRα-Tg sham, #P = 0.01.
Figure 5A LV/tibia ratios in sham- and TAC-operated WT and LXRα−/− mice; n = 10 WT sham, n = 8 LXRα−/− sham, n = 12 WT TAC, n = 10 LXRα−/− TAC. *P = 0.006 versus WT sham, **P = 0.00008 versus LXRα−/−sham.B, C Cardiac functional assessment at 5 weeks post-TAC. (B) Percent fractional shortening determined with echocardiography; n = 10 WT sham, n = 7 LXRα−/− sham, n = 12 WT TAC, n = 10 LXRα−/− TAC. *P < 0.00001 versus respective sham, §P = 0.06. (C) LV end-diastolic pressure (LVEDP) recorded in situ; n = 10 WT sham, n = 7 LXRα−/− sham, n = 10 WT TAC, n = 9 LXRα−/−TAC. *P = 0.001 versus WT sham, **P = 0.00005 versus LXRα−/− sham.D-G Relative mRNA gene expression as determined by RT-PCR, normalized to 36b4; n = 8/group. Anp: no significant differences; Bnp: *P = 0.01 versus WT sham, **P = 0.03 versus LXRα−/− sham; Myh6/Myh7: *P = 0.0002 versus WT sham, **P = 0.0003 versus LXRα−/− sham; Acta1: *P = 0.001 versus respective sham.H Western blot detection of GLUT protein expression in LV tissue normalized to GAPDH, expressed as fold change, shows no significant differences among groups; n = 6-8/group.I Representative 18F-FDG-microPET scans.J Myocardial FDG uptake quantified as standard uptake value (SUV); n = 6/group. *P = 0.0001 versus WT sham, #P = 0.047.
Figure 6A Assessment of 2-deoxyglucose (2-DG) uptake from 4 independent experiments. *P = 0.03 versus Ad-cont.B, C Glut mRNA expression determined by RTD Western blot indicating Ad-LXRα- and PE-induced increases in global protein O-GlcNAcylation, which was abrogated following inhibition of HBP with DON. LXRα protein expression is shown, and GAPDH served as a loading control.E, F Modulation of Anp and Bnp mRNA levels by Ad-LXRα-induced O-GlcNAc signaling. Gene expression as determined by RT-PCR normalized to 36b4, n = 5 per condition in the absence of PE, n = 4 per condition in the presence of PE. *P = 0.02 versus Ad-cont, **P = 0.008 versus Ad-cont, #P = 0.03, ##P = 0.02.G Measurement of cell size, n = 5 per condition. *P = 0.008 versus Ad-cont, #P = 0.02, ##P = 0.03.H Representative images for the determination of cell size. Cells were stained with an antibody specific for LXRα (green, indicated by arrow), DAPI for nuclei (blue), and rhodamine-phalloidin for F-actin (red); scale bar = 50 μm.
Figure 7A Protein synthesis determined via leucine incorporation, n = 2-4 independent experiments. *P = 0.03 versus Ad-cont, §P = 0.06 versus Ad-cont.B Global O-GlcNAc protein expression with Western blot, GAPDH served as a control.C-F mRNA expression, normalized to 36b4, n = 6 per condition, except n = 5 for si-LXRα control. Anp: *P = 0.009 versus Ad-cont, #P = 0.004, ##P = 0.009; Bnp: *P = 0.004 versus Ad-cont, **P = 0.002 versus Ad-cont; Acta1: *P = 0.002 versus Ad-cont, §P = 0.06 versus Ad-cont, #P = 0.02; Rcan1: *P = 0.03 versus Ad-cont, **P = 0.004 versus Ad-cont, #P = 0.004.
Figure 8A, B Western blot analyses of global protein O-GlcNAc levels in left ventricles of mice with either (A) cardiac-specific LXRα overexpression or (B) LXRα deficiency and subjected to 5 weeks TAC.C, D Nuclear protein extracts were precipitated with agarose WGA in the absence or presence of GlcNAc, a competitor, and analyzed by Western blot with antibodies against Mef2c, GATA4, or Nkx-2.5, known transcription factors of natriuretic peptides; bands represent 3 pooled hearts per Wt and LXRα-Tg lanes, and (D) quantification is for n = 2, expressed as fold change.
Figure 1C) Results of a competitive uptake assay showing inhibition of 0.2 µM L-[3H]Trp or L-[3H]Leu uptake in MhsT-WT-expressing MQ614 cells, measured for 30 seconds in the absence (-) or presence of 12 µM of the natural amino acids (the one-letter code is used) or 4-fluoro-phenylalanine (4FP). Data are the mean ± S.E.M. of three independent experiments each performed as technical triplicates.
Figure 5A) Uptake of 0.1 μM L-[3H]Leu was measured for 10-second periods in the presence or absence of the indicated natural amino acids and 4-fluorophenylalanine (4FP, all compounds tested at 100 μM final concentration) in MQ614 expressing MhsT-WT or -M236F.B, C) Time course of 0.1 µM L-[3H]Leu (B) or 0.1 µM L-[3H]Trp (C) by MQ614 expressing MhsT-WT () or -M236F (), or MQ614 transformed with the control plasmid, pQE60 ().D, E) Kinetics of L-[3H]Leu (D) or L-[3H]Trp (E) uptake.
Figure 1(A) EGFR degradation was followed in MSD, MPS‐IIIA and WT MEFs by treating the cells with EGF for the indicated time to stimulate EGFR internalization. The cells were then immediately lysed and subjected to anti‐EGFR blotting. The amount of remaining EGFR was quantified by densitometry analysis (Image J) of the blot and expressed in the chart as % of the EGFR amount present at time T0 (100%). The values in the chart represent the mean±s.e.m. values of three independent experiments.(B) MSD, MPS‐IIIA and WT MEFs cells loaded with dextran (alexafluor‐594 conjugated) were labelled with anti‐LAMP1 antibody and the percentage of dextran co‐localizing with LAMP1 was evaluated. The chart displays merge values (means±s.e.m.) that represent the percentage of dextran co‐localizing with LAMP1 measured in 15 different cells of triplicate experiments.(C) The rate of lysosome fusion with autophagosomes was monitored in MSD, MPS‐IIIA and WT MEFs transfected with a tandem fluorescently tagged LC3 ( Kimura et al, 2007). The rate of autophagosome maturation reflected the percentage of the LC3 'unfused' (green/red fluorescence ratio) at each time (1 and 3 h) after bafilomycin removal (T0). The percentage of LC3 'unfused' was displayed versus the value at T0 (assumed to be 100%). Values are represented as means±s.e.m. of triplicate experiments. *P0.05, Student's t‐test: (A): WT versus MSD and WT versus MPS‐IIIA; (B, C): WT versus MSD and WT versus MPS‐IIIA at each time point. Scale bar: 10 μm (B, C).
Figure 2(A) Cholesterol levels were measured in the indicated endolysosomal membrane samples containing equal amount of proteins and expressed as ng of cholesterol per μg of protein (see Materials and methods section for details).(B) Filipin staining showing cholesterol accumulation in the endolysosomal compartment of MSD and MPS‐IIIA MEFs (arrowheads and enlarged images).(C, D) Total lipids extracted from the indicated endolysosomal membrane samples (30 μg of proteins) were either (C) subjected to a phosphate assay to quantify the bulk of phospholipids or (D) separated by TLC. Phospholipids and cholesterol on TLC plates were revealed by molybdenum blue staining. CHOL, cholesterol; LBPA lysobisphosphatidic acid; PC, phosphatidylcoline; PE phosphatidylethanolamine; PI phosphatidyinositol; SM sphingomyelin. (A, C) Values represent the mean±s.e.m. values of three independent experiments. *P0.05, Student's t‐test: (A, C): WT versus MSD and WT versus MPS‐IIIA. Scale bar, 10 μm (B).
Figure 4(A) Endolysosomal membranes from MSD, MPS‐IIIA and WT MEFs were treated with 1% Triton X‐114 and loaded on a sucrose gradient. Immunoblots with Flotillin‐1 identified DRMs in fractions 2, 3 and 4 (arrows). The fractions at the bottom of the gradient (12 and 13) correspond to high‐density detergent soluble fractions, whereas the remaining ones were defined as intermediate fractions (intermediate‐I: 5, 6, 7 8; intermediate‐II: 9, 10 and 11). The percentage of Flotillin‐1 in DRMs was calculated from the densitometric quantification of immunoblots.(B) Immuno‐EM of GM1 lipid was carried out in WT, MSD and MPS‐IIIA MEFs by staining cells with anti‐cholera toxin B antibodies (see Materials and methods section). The number of GM1‐positive dots was measured in 25 cells from three independent experiments and displayed as fold to WT.(C) Endolysosomal membranes from MSD, MPS‐IIIA and WT MEFs were stained with C‐laurdan and subsequently analysed by fluorescence spectrophotometry to calculate the GP value (see Materials and methods section for details). Distribution of cholesterol was also measured throughout the gradient ad expressed as percentage of total cholesterol in raft (DRMs) and soluble fractions.(D) Equal aliquots from either DRMs or soluble fractions were pooled, the protein content determined and displayed as percentage of total protein in DRM and soluble gradient regions.(E) Immunoblotting profiles of the transferrin receptor and LAMP1 in the sucrose gradient. Values represent the mean±s.e.m. values of three experiments (A-D). *P0.05, Student's t‐test: (A-C): WT versus MSD and WT versus MPS‐IIIA; (D): WT versus MSD and WT versus MPS‐IIIA for each fraction. Scale bar: 0.3 μm (B).
Figure 5(A) VAMP7, Vti1b and syntaxin 7 distributions in endo‐lysosomal membranes from MSD, MPSIIIA and WT MEFs was evaluated by immonoblotting analysis of gradient fractions. To simplify the analysis the DRM, the intermediate‐I, the intermediate‐II and soluble fractions of the gradient were pooled separately and then subjected to immunoblotting. SNARE distribution was also analysed after loading WT cells with cholesterol and after MβCD treatment. In MSD and MPS‐IIIA MEFs, all analysed SNAREs abnormally accumulate in DRMs of lysosomal membranes. Cholesterol modulation results in a change of SNARE distribution.(B) The percentage of each analysed SNARE observed in DRM fractions was quantified from blots (ImageJ densitometry analysis) and displayed as relative amount versus WT.(C, E) Immunoblots and relative quantification showing SNARE protein levels along with LAMP1 protein levels in (C) endolysosomal membranes and (E) total cell lysates from WT (untreated and cholesterol treated) and MSD MEFs (untreated and MβCD treated). In the graphs, the protein levels were displayed as relative amount versus WT.(D) WT and MSD MEFs transfected with GFP-VAMP7 were stained with anti‐GFP for immuno‐EM. The enlarged image shows internalization of GFP-VAMP7 particles (arrow).(F) Syntaxin 5, Sec22 and SNAP23 distribution in total membrane derived from control WT and MSD MEFs. Syntaxin 5 immunoblot shows two bands (*, 35 kDa and **, 42 kDa) corresponding to the two isoforms of the protein.(G) Distribution profile of Rab7 in WT and MSD lysosomal membranes. Values represent the mean±s.e.m. values of three independent experiments (B, C, E). *P0.05, Student's t‐test: (B): WT versus MSD, WT versus MPS‐IIIA, WT versus WT+cholesterol, MSD versus MSD+MβCD, and MPS‐IIIA versus MβCD for each analysed SNARE; (C, E): WT versus MSD, WT versus WT+cholesterol and MSD versus MSD+MβCD for each analysed protein. Scale bar: 0.3 μm (D).
Figure 6(A) SDS‐resistant complexes containing Vti1b were detected by immunoblotting analysis of nonboiled samples corresponding to total, detergent insoluble (DRM) and detergent soluble (Sol.) endo‐lysosomal membrane fractions derived from MSD and WT MEFs. The SDS‐resistant complexes were also visualized after loading WT MEFs with cholesterol and after treating MSD MEFs with MβCD. Immunoblots revealed the presence of low molecular weight complexes (*, 50-60 kDa) and high molecular weight complexes (**, >80 kDa). The percentage of Vti1b in SDS‐resistant complexes in total endolysosomal membranes (bottom‐left chart) and the amount of Vti1b‐containing SDS‐resistant complexes in DRM and soluble fractions (bottom‐right chart) were calculated by the densitometric quantification of the correspondent immunoblots (ImageJ). Values represent the mean±s.e.m. values of three independent measurements. *P0.05, Student's t‐test: WT versus MSD, WT versus WT+cholesterol and MSD versus MSD+MβCD (bottom‐left chart); WT versus MSD, WT versus WT+cholesterol and MSD versus MSD+MβCD for each fraction (bottom‐right chart).(B) Syntaxin 7 and VAMP7 were co‐immunoprecipitated with Vti1b using anti‐Vti1b antibodies in WT (untreated or cholesterol treated) and in MSD (not treated or MβCD treated) MEFs. The amount of Vti1b precipitated in each cell line is also shown.(C) SDS‐resistant complexes are decorated by anti‐syntaxin 7 antibodies in total endolysosomal membrane fraction from WT and MSD MEFs.(D) Membrane‐associated α‐SNAP and its release in the cytosol were evaluated by western blot analysis on total cell lysates (total), intracellular membranes recovered after centrifugation from a post‐nuclear supernatant fraction (membrane associated) and cell lysates devoid of membranes (cytosolic released) derived from MSD (untreated or MβCD treated) and WT (untreated or cholesterol treated) MEFs.
Figure 7(A) MSD, MPS‐IIIA and WT MEFs were subjected to a triple labelling with anti‐VAMP7, anti‐Vti1b and anti‐LAMP1 antibodies. The merges between VAMP7 and Vti1b (double merges in yellow) and between VAMP7, Vti1b and LAMP1 (triple merges in white) are shown (see also enlarged images showing the extent of co‐localization in different regions of the cells). The VAMP7-Vti1b co‐localization was quantified in 15 different cells and displayed as % of Vti1b co‐localizing with VAMP7 (means±s.e.m.).(B) Co‐localization of Vti1b with epsinR was quantified by double‐labelling experiments in MSD and MPS‐IIIA (untreated and MβCD treated) and in control WT (untreated and cholesterol treated) MEFs. The chart displays merge values (means±s.e.m.) that represent the percentage of Vti1b co‐localizing with epsinR measured in 15 different cells.(C) Vti1b trafficking was monitored by FRAP analysis in WT (untreated and cholesterol treated) and MSD (untreated and MβCD treated) MEFs transfected with GFP-Vti1b (see Materials and methods section for details). FRAP data are displayed as percentage of recovery with respect to the fluorescence before bleach (100%) and are representative of 10 recordings from different cells.