This chapter examines how constraints on the motility of individual components—such as symbionts and organelles—within eukaryotic cells affect their autonomous interactive capacities and how this influences the constitutive autonomy of the entire collective association. It argues that while the motility of most symbionts and organelles is controlled by the host, this control is exercised in different ways. Symbionts may lose their motile abilities but retain the capacity to interact autonomously with the host, with interactive processes controlled internally rather than by the host. In contrast, organelles lose their autonomous motility entirely but are moved via cytoskeletal-driven mechanisms controlled by the eukaryotic cell. The chapter contends that the emergence and maintenance of collective biological identities involve stringent regulation of the motile abilities of their constituent parts. This regulation restricts, but does not necessarily eliminate, the agential capacities of individual components.