Figure 3.

Working model of TAN line structure and function. (A) Illustration of the molecular composition of a TAN line. INM, inner nuclear membrane; ONM, outer nuclear membrane. (B) Depiction of TAN line behavior during centrosome orientation under different conditions. TAN lines in wild type cells (left) form on the dorsal surface of the nucleus and function to harness the forces generated by the actin cytoskeleton to move the nucleus rearward while the centrosome remains stationary resulting in centrosome orientation towards the leading edge. In nesprin-2G-depleted cells (middle) TAN lines do not form resulting in the lack of nuclear movement and centrosome orientation. In lamin A/C- or SUN2-depleted cells (right), nesprin-2G TAN lines form but are unanchored causing them to slip over the surface of the nucleus with the rearward moving actin cables. Neither nuclear movement nor centrosome orientation occurs in this situation.