Profilin as a dual regulator of actin and microtubule dynamics

Although originally identified as G-actin sequestering proteins, profilins are emerging as critical regulators of actin dynamics, capable of interacting with multiple acting binding proteins, and being able to link membrane lipids to cytoskeleton components. Recently, in addition to its actin, poly-proline, and phosphatidylinositol binding domains, profilin has been shown to contain residues specialized in microtubule binding. Here we will discuss in a critical perspective the emerging body of data supporting that profilins are central mediators of actin microfilament and microtubule interaction. We will also address the unanswered questions in the field, including the nature of the interaction of profilin with microtubules, and its effect on microtubule dynamics. These recent discoveries deepen our understanding on how different cytoskeleton components are integrated within cells.