Journal of Cell Science 116, e1301 (2003)
Copyright © 2003 The Company of Biologists Limited
Formin' actin filaments
Formation of new actin filaments is essential for cell movement, growth and
division. The Arp2/3 complex is a well-established nucleator of actin
filaments, but recent work has revealed that there are other players in this
game: the formins. In a Commentary on
p. 2603, Charles Boone and
co-workers discuss work illuminating the roles of these proteins, which can
nucleate actin filaments in vitro and are implicated in numerous
actin-dependent processes. Formins contain two conserved domains: FH2, which
probably mediates filament nucleation; and FH1, which might facilitate
delivery of actin monomers to growing filaments by interacting with the
G-actin-binding protein profilin. Recent work indicates that regulation of
formin activity, in at least some cases, depends on additional, N-terminal
sequences; in the case of formins related to the protein Diaphanous, for
example, these interact with the small GTPase Rho, allowing the molecules to
function as effectors in Rho signalling. Other studies indicate that formins
are important for spindle positioning in yeast and modulate microtubule
organization in mammalian cells. Indeed these proteins appear to link the
microtubule and actin filament systems and thereby help to establish cell
polarity.
Related articles in JCS:
- Formins: signaling effectors for assembly and polarization of actin filaments
- Marie Evangelista, Sally Zigmond, and Charles Boone
JCS 2003 116: 2603-2611.
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