Membrane tension is thought to be a long-range integrator of cell physiology. This role necessitates effective tension transmission across the cell. However, the field remains strongly divided as to whether cell membranes support or resist tension propagation, in part due to a lack of adequate tools for locally manipulating membrane tension. We overcome these limitations by leveraging optogenetics to generate localized actin-based protrusions while concurrently monitoring the propagation of membrane tension using dual-trap optical tweezers. Surprisingly, actin-driven protrusions elicit rapid global membrane tension propagation with little to no attenuation, while forces applied to the cell membrane only do not. We present a simple unifying mechanical model in which mechanical forces that act on both the membrane and actin cortex drive rapid, robust membrane tension propagation.

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