Distinct actin architectures across a giant syncytial cell.

The syncytial slime mold Physarum polycephalum exhibits cytosolic streaming, cell migration, and cell network remodeling within a single cell. It is unclear how cytoskeletal elements are spatiotemporally organized to mediate these processes. Here, we combine live and fixed imaging of Physarum F-actin to uncover organizational and dynamic signatures of the actin cytoskeleton across cell structures. We find circumferential actin filaments constrict and relax to drive peristaltic contractions in feeding tubes, while migratory fans are characterized by actin patches and comets. Our work presents undescribed actin structures in Physarum and demonstrates that different actin-based behaviors coexist within a contiguous cytoplasm.