An instrument includes a movable end effector component coupled to a shaft; a force transmission mechanism; and an actuation mechanism coupled to the force transmission mechanism and the end effector, the actuation mechanism comprising a first actuation member segment and a second actuation member segment. The force transmission mechanism comprises: a first pulley coupled to a rotatable drive input and having a first axis of rotation, and a second pulley having a second axis of rotation non-parallel to the first axis of rotation of the first pulley. The first actuation member segment is routed over the first pulley. In response to rotation of the rotatable drive input, at least a portion of the first actuation member segment is wound onto the first pulley and unwound from the second pulley, and the second actuation member segment is translated along the shaft to actuate the movable end effector component.