A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
A high-affinity interaction with ADP-actin monomers underlies the mechanism and in vivo function of Srv2/cyclase-associated protein
Tekijät: Mattila PK, Quintero-Monzon O, Kugler J, Moseley JB, Almo SC, Lappalainen P, Goode BL
Kustantaja: AMER SOC CELL BIOLOGY
Julkaisuvuosi: 2004
Journal: Molecular Biology of the Cell
Tietokannassa oleva lehden nimi: MOLECULAR BIOLOGY OF THE CELL
Lehden akronyymi: MOL BIOL CELL
Vuosikerta: 15
Numero: 11
Aloitussivu: 5158
Lopetussivu: 5171
Sivujen määrä: 14
ISSN: 1059-1524
DOI: https://doi.org/10.1091/mbc.E04-06-0444
Cyclase-associated protein (CAP), also called Srv2 in Saccharomyces cerevisiae, is a conserved actin monomer-binding protein that promotes cofilin-dependent actin turnover in vitro and in vivo. However, little is known about the mechanism underlying this function. Here, we show that S. cerevisiae CAP binds with strong preference to ADP-G-actin (K-d 0.02 muM) compared with ATP-G-actin (K-d 1.9 muM) and competes directly with cofilin for binding ADP-G-actin. Further, CAP blocks actin monomer addition specifically to barbed ends of filaments, in contrast to profilin, which blocks monomer addition to pointed ends of filaments. The actin-binding domain of CAP is more extensive than previously suggested and includes a recently solved beta-sheet structure in the C-terminus of CAP and adjacent sequences. Using site-directed mutagenesis, we define evolutionarily conserved residues that mediate binding to ADP-G-actin and demonstrate that these activities are required for CAP function in vivo in directing actin organization and polarized cell growth. Together, our data suggest that in vivo CAP competes with cofilin for binding ADP-actin monomers, allows rapid nucleotide exchange to occur on actin, and then because of its 100-fold weaker binding affinity for ATP-actin compared with ADP-actin, allows other cellular factors such as profilin to take the handoff of ATP-actin and facilitate barbed end assembly.
Ladattava julkaisu This is an electronic reprint of the original article. |  |
