DNM activity is required for optimal PPF and adequate demarcation membrane system (DMS) development. (A-B) PPF representative fields on microscopy imaging and proplatelet (PPT) quantification. PPT stalks are shown with arrow. DNSR-treated MKs had reduced PPF by almost half (paired Student t test P ≤ .01). Images taken by a Nikon Eclipse TS100 (×40 objective) and INFINITY capture camera and software (Luminera), analyzed with INFINITY Analyze software (Luminera). Scale bar represents 100 µm. (C) GpIb (CD42; red) staining of MK plasma membrane and intracellular DMS. Clumps, clustering, and uneven distribution of the DMS were observed within DNSR-treated MKs when compared with control (CTRL) MKs (arrows; supplemental Videos 3 and 4). The CD41 staining (green) showed the same trend of poor distribution within DNSR-treated MKs when compared with CTRL MKs. The nucleus is stained in blue. Images taken by Nikon A1R+ confocal microscope under a 60× Plan-Apochromat oil immersion lens. Scale bar represents 5 µm. (D-E) Representative flow cytometry histograms and flow cytometry quantification of CD41 at the surface of MKs. DNSR-treated MKs showed increased surface expression of CD41 (by 25%; paired Student t test P < .05). Error bars indicate standard errors of the mean of ≥3 independent experiments. *P ≤ .05, **P ≤ .01.