The PH domain of Myo1c is required for its recruitment during WPB exocytosis. (A) A schematic of the proposed spatiotemporal dynamics of Myo1c recruitment during WPB exocytosis. (B) Live cell imaging of the GFP-PIPK1γ87 and P.sel.lum.mCherry in secretagogue (HAI) stimulated HUVEC illustrates postfusion recruitment. Two exocytic events are seen here. Scale bars are 1 μm. White and magenta arrows indicate independent fusion events. (C) The PIP2 sensor PH-PLCδ1-GFP is also recruited after fusion. Scale bars are 1 μm. (D) A schematic of the Myo1c structural domains and location of truncation or site directed mutations. (E) HUVEC coexpressing LifeAct-Ruby and Myo1c-Tail+3IQ-GFP indicated the importance of the myosin head domain for interacting with actin. Scale bars are 10 μm. (F) Myo1c-Tail+3IQ-GFP is recruited to WPBs after fusion. (G-H) GFP-tagged Myo1c fusion proteins harboring mutations in their PH domain (K892A/R903A) are not recruited to WPBs during exocytosis. Scale bars are 10 μm (F,G,H). Inset scale bars are 1 μm. For live cell confocal imaging experiments, 0.5 μm Z stacks were acquired continuously for 5 to 10 minutes (Zeiss LSM 800).