Biology Reference
In-Depth Information
Do Class I Myosins exert their
Functions through Regulation of
Actin Dynamics?
Thierry Soldati
and
Claudia Kistler
Since the discoveries of class I myosins, the first non-muscle myosins, about
30 years ago, their history has been linked both to the organization and
working of actin filaments and to their connection to membranes, especially
the plasmalemma. Indeed, the early biochemical characterization highlighted
the capacity of these mechanochemical enzymes to crosslink actin filaments
and to bind phospholipids. Recent findings shed new light on these
relationships and reveal a more active role of class I myosins in regulating
the spatial and temporal nucleation and elongation of actin filaments in close
proximity of membrane sites determined by signalling and cell polarity
mechanisms. The understanding of the role of the actin cytoskeleton in cell
motility has recently made a giant leap forward with the discovery and
dissection of the major actin nucleator, the Arp2/3 complex, and some of its
activators. To investigate the molecular and cellular bases of the integration
of myosin motor activity and actin dynamics in cortical management and cell
motility, we make use of a genetically and biochemically tractable model
organism, Dictyostelium discoideum. As the components of these complex
machineries are evolutionarily conserved, their molecular and cellular
dissection in D. discoideum is directly relevant to unravel their functional
importance in higher organisms.
