Figure 3. Actin dynamics shape MRCKβ... | Rockefeller University Press

Figure 3.

$Actin dynamics shape MRCKβ ring distribution in the polarized cortex. (A) Immunofluorescence detection of MRCKβ in MII oocytes treated with DMSO (top), CK-666 (100 µM, 3 h; middle), or Latrunculin A (LatA; 0.5 µM, 10 min; bottom). Arrows point to MRCKβ redistributed as a polarized cap. (B) Bar graph depicting the fraction of MII oocytes (%) showing MRCKβ distributed as a ring or as a cap, as shown in A. Oocytes were treated with DMSO (control), CK-666, or Latrunculin A (LatA), as shown in A. Oocytes in which the MII spindle had relocated to the center after CK-666 treatment, resulting in a complete loss of polarized MRCKβ, were not considered for analysis. P values were calculated using Fisher’s exact test. The number of oocytes scored is indicated above each bar. (C) Immunofluorescence detection of activated myosin II (P-MRLC) and MRCKβ in MII oocytes treated for 1 h with DMSO (top) or BDP9066 (1 µM; bottom). (D) Detection of Cdc42·GTP in an MII oocyte expressing the biosensor MCB-EGFP. Fluorescence intensity profiles correspond to the polarized cortex region delineated by the two gray arrowheads in the merged images. F-actin was labeled with Alexa Fluor 568–phalloidin. Chromosomes were stained with TO-PRO-3 (magenta). Scale bars are 10 µm. PB1: first polar body.$

Actin dynamics shape MRCKβ ring distribution in the polarized cortex. (A) Immunofluorescence detection of MRCKβ in MII oocytes treated with DMSO (top), CK-666 (100 µM, 3 h; middle), or Latrunculin A (LatA; 0.5 µM, 10 min; bottom). Arrows point to MRCKβ redistributed as a polarized cap. (B) Bar graph depicting the fraction of MII oocytes (%) showing MRCKβ distributed as a ring or as a cap, as shown in A. Oocytes were treated with DMSO (control), CK-666, or Latrunculin A (LatA), as shown in A. Oocytes in which the MII spindle had relocated to the center after CK-666 treatment, resulting in a complete loss of polarized MRCKβ, were not considered for analysis. P values were calculated using Fisher’s exact test. The number of oocytes scored is indicated above each bar. (C) Immunofluorescence detection of activated myosin II (P-MRLC) and MRCKβ in MII oocytes treated for 1 h with DMSO (top) or BDP9066 (1 µM; bottom). (D) Detection of Cdc42·GTP in an MII oocyte expressing the biosensor MCB-EGFP. Fluorescence intensity profiles correspond to the polarized cortex region delineated by the two gray arrowheads in the merged images. F-actin was labeled with Alexa Fluor 568–phalloidin. Chromosomes were stained with TO-PRO-3 (magenta). Scale bars are 10 µm. PB1: first polar body.

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