The Molecular Mechanisms of Actin Regulatory Proteins pp. 207-227
Authors: (Barak Reicher, Mira Barda-Saad, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel)
Abstract: Actin polymerization is the driving force behind multiple cellular processes
including proliferation, motility, adhesion and endocytosis, providing the infrastructure
for structural cellular remodeling and intracellular signal transduction. The variety and
flexibility of cellular function is achieved by the formation of diverse actin structures. de
novo formation of actin filaments is controlled by a combination of G-actin binding
proteins, actin severing proteins, and capping factors. In order to overcome these
regulatory checkpoints and support efficient actin polymerization, the orchestrated
activity of various actin elongation and nucleation proteins, such as formins and the
ARP2/3 complex is required.
This delicate balance between actin polymerization and de-polymerization must be
highly controlled to ensure the formation of the correct actin structures at the correct
place and time.
The highly controlled actin polymerization process is enabled by the activity of actin
nucleation promoting factors (NPFs). These proteins are present in molecular complexes
that associate with actin nucleation proteins and are involved in their stabilization and
activation at actin-rich sites.
These complexes work in concert to control the spatial and temporal formation of
diverse actin structures.
Recently, the development of cutting-edge imaging technologies have provided new
insights into the regulatory mechanisms of the NPFs, and their modes of activation,
dynamics and association with the actin nucleation proteins.