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. Author manuscript; available in PMC: 2021 Jun 3.
Published in final edited form as: Cell Rep. 2021 May 18;35(7):109146. doi: 10.1016/j.celrep.2021.109146

Figure 4. Membrane domains mediate aPKC polarity maintenance.

Figure 4.

(A) Membrane and aPKC dynamics in a neuroblast in which membrane domains were removed via cyclodextrin treatment. Selected frames subsequent to polarization are shown from Video S7. Time is shown in minutes and seconds relative to NEB.

(B) Gardner-Altman estimation plot of the effect of cyclodextrin on the cortical recruitment of aPKC. Apical cortical to cytoplasmic signal intensity ratios of GFP-aPKC are shown for individual metaphase neuroblasts treated with cyclodextrin. Statistics: bootstrap 95% confidence interval.

(C) Neuroblast expressing mCherry-PH and aPKC RNAi. Selected frame from Video S8.

(D) Comparison of GFP-Miranda in untreated and cyclodextrin-treated neuroblasts (anaphase) shown in medial sections. MIPs for the same neuroblasts are shown in Video S9.

(E) Gardner-Altman estimation plot of the effect of cyclodextrin on the cortical recruitment of Miranda. Basal cortical to cytoplasmic signal intensity ratios of GFP-Miranda are shown for individual anaphase neuroblasts treated with cyclodextrin. Statistics: bootstrap 95% confidence interval.

(F) Membrane and aPKC maintenance dynamics in a neuroblast in which the actin cytoskeleton was disrupted by treatment with LatA. Selected frames following LatA addition are shown from Video S10.

(G) Model for neuroblast membrane dynamics. Membrane features are dispersed over the entire cell surface during interphase and progeny cell contacts are typically restricted to the basal pole. Apically directed movements begin in prophase, when aPKC is recruited to the apical hemisphere of the membrane (enriched at membrane domains and diffuse elsewhere), and movements lead to metaphase polarization and deformation of progeny contacts. Basally directed movements begin in anaphase and depolarize membrane features and return progeny cell contacts to the basal hemisphere.