The gelsolin:calponin complex nucleates actin filaments with distinct morphologies.
Gelsolin and calponin are cytoskeletal and signalling proteins that form a tight 1:1 complex (GCC). We show that calponin within the GCC inhibits the rate of gelsolin mediated nucleation of actin polymerization. The actin-binding function of calponin is ablated within the GCC as the actin-binding site overlaps with one of the gelsolin binding sites. The structure of filaments that result from nucleation by GCC are different to those nucleated by gelsolin alone in that they are longer, loosely bundled and stain heterogeneously with phalloidin. GCC nucleated filaments appear contorted and wrap around each to form the loose bundles.
Ferjani
Imen
I
DIMNP, University of Montpellier 2 and 1, CNRS Montpellier, Place E. Bataillon CC107, 34095 Montpellier Cedex 5, France.
Fattoum
Abdellatif
A
Bettache
Nadir
N
Seantier
Bastien
B
Milhiet
Pierre-Emmanuel
PE
Manai
Mohamed
M
Benyamin
Yves
Y
Roustan
Claude
C
Maciver
Sutherland K
SK
D008841:Actin Cytoskeleton / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D018260:Gelsolin / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008840:Microfilament Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D008854:Microscopy, Electron; D000096985:Calponins
D002135:Calcium-Binding Proteins; D018260:Gelsolin; D008840:Microfilament Proteins; D000096985:Calponins