Interaction of actin filaments with microtubules is mediated by microtubule-associated proteins and regulated by phosphorylation.

Abstract

We have reconstituted high viscosity networks of actin filaments and microtubules from purified actin, tubulin, and MAPs. MAP-2 can effectively cross-link actin filaments and microtubules, presumably because a low affinity actin binding site is available even when it is bound tightly to microtubules. Phosphorylation of MAP-2 inhibits cross-linking of actin filaments and microtubules. Tau is not an effective cross-linker of actin and microtubules even though it can interact with each polymer individually.