Stress fibers form as dorsal and ventral fibers and arcs.
Cells contain at least three different types of contractile actin-based stress fibers. Transverse arcs do not associate with focal adhesions on either end, whereas ventral stress fibers contact focal adhesions on both ends. Dorsal stress fibers have one end tied to a focal adhesion on the ventral side of the cell and frequently attach to a transverse arc with the other end.
Using live cell microscopy and a variety of fluorescently tagged proteins, Hotulainen and Lappalainen found that dorsal stress fibers and transverse arcs underwent continuous de novo formation and disassembly. The ventral fibers, in contrast, were formed by fusion of dorsal and transverse fibers.
Dorsal fiber formation initiated at focal adhesions and was dependent on the mDia1 formin, which...
