Integration of evolutionarily distinct motility systems enables tunable cell propulsion

Motility allows cells to explore their surroundings, evade threats, and coordinate collective behaviors. Many organisms, from bacteria to animals, encode more than one motility system, yet whether and how mechanistically distinct systems are integrated within individual cells remains largely unresolved. We address this question in the predatory bacterium Myxococcus xanthus, which navigates surfaces using two mechanistically and evolutionarily distinct motors: focal-adhesion-based gliding and type IV pili-driven twitching. For this, we develop an imaging-based quantitative behavioral phenotyping method to show that both motors are simultaneously active within individual cells and jointly power cell movement. Cells engaging both motors move faster and explore space more effectively than cells using either motor alone, expanding locomotion performance. Extracellular calcium tunes their relative contributions, progressively shifting cells from gliding- to twitching-dominated propulsion. Unexpectedly, the gliding motor can boost twitching even without anchoring to the surface, revealing that cooperation between motility systems extends beyond simultaneous force generation. Together, these findings reveal that evolutionarily distinct motility systems can function as components of a single, environmentally tunable propulsion strategy.