Fig. 4

Kif2 protein localizes to the domain of cortical ER in the CAB. a CAB is a multilayered cortical structure rich in cortical ER. pMNK labeling of the cortical ER (green) with the mitochondria labeled with anti NN18 (red) and the DNA with DAPI (blue). Enlarged view of the ROI showing that the mitochondria are excluded from the CAB where the cER is enriched (oval). Scale bar = 30 µm. n > 50. b Kif2 is localized to cortical endoplasmic reticulum. Schematic of cortical preparation, ER in red. Top right: probing cortical preparations with DiO (green) to label the endoplasmic reticulum and Kif2 antibody (red) revealed that Kif2 protein was localized to the domain of cortical ER in the CAB. CAB is indicated in boxed region. Lower: enlarged views of the boxed region in top right images showing more clearly the cER labeled with a DiO (green) together with the Kif2 labeling (red). At the edge of the CAB some tubes of cER are visible (insets of small boxed regions) where Kif2 fluorescence appears punctate relative to the green DiO cER signal. Scale bars = 10 µm. n > 50. See Supplementary Movie 9. c Kif2 finger-like projections at CAB surface during mitosis. Embryo containing Kif2::Tom, EB3::GFP and H2B::GFP. During mitosis red finger-like projections appear at the surface of the CAB (arrows). Mitotic stage is indicated from H2B::GFP labeling of chromosomes during mitosis (left boxed region). Enlarged views of the two boxed regions showing the finger-like projections from the CAB surface (upper row of images) and the mitotic stage as indicated by the chromosome configuration. Scale bar = 20 µm