The radial spoke of each group of radial spokes, whether grouped as triplets or doublets, that is immediately distal to radial spoke 1 (RS1). Radial spoke 2 (RS2), similarly to RS1, is comprised of four domains: 1) a very short base anchored to the A microtubule, 2) an elongaged stalk, 3) a bifurcated neck, and 4) an orthogonal head. The base of RS2 is connected to the tail of the inner dynein arm c.
RS2