Orthogonal arrays have different size and diffusional mobility in somatic and lamellipodial plasma membrane of cells expressing both M1– and M23–AQP4. (A) Left panels show TIRF images of AQP4 and F-actin in U87-MG cells cotransfected with M1– and M23–AQP4, and in wild-type astrocyte cultures (that express both isoforms). Right panels show reconstructed dSTORM images of AQP4 from the indicated areas (white boxes). (B) Cumulative distribution of AQP4 by array size in lamellipodial and somatic regions from cells shown in A. (C) Qdot single-particle tracking of AQP4 in lamellipodial and somatic regions of wild-type astrocytes (top panels) with representative trajectories from lamellipodial and somatic areas shown in bottom panels. (D) Pooled analysis of 216 somatic and 80 lamellipodial trajectories from 10 cells shown as the average mean-squared displacement vs. time (top) and cumulative probability plots of range at 1 s (middle) and short-range (0–100 ms) diffusion coefficient (bottom).