Density of actin filament binding sites

Value 0.02 1/nm^2
Organism Fission yeast Schizosaccharomyces pombe
Reference Chen Q, Pollard TD. Actin filament severing by cofilin dismantles actin patches and produces mother filaments for new patches. Curr Biol. 2013 Jul 8 23(13):1154-62. doi: 10.1016/j.cub.2013.05.005. p.8 left column 4th paragraphPubMed ID23727096
Primary Source Kukulski, W., Schorb, M., Kaksonen, M., and Briggs, J.A. (2012). Plasma membrane reshaping during endocytosis is revealed by time-resolved electron tomography. Cell 150, 508–520.PubMed ID22863005
Method "[Researchers] used quantitative fluorescence microscopy to track mGFP-tagged proteins, including early endocytic adaptor proteins, activators of Arp2/3 complex, and actin filaments."
Comments "Actin filament binding sites on adaptor proteins Pan1p and End4p are important to initiate actin nucleation in patches. The affinities of the APW motif of Pan1p and the TLD domain of End4p for actin filaments (Kd=~3µM) are higher than alpha-actinins (Kd=20µM), which bind actin filaments in physiological settings. Given 240 molecules of End4p and Pan1p on the tiny surface of a coated pit (12,000nm^2, assuming a diameter of 50nm [primary source]), the density of actin filament binding sites is 1/50nm^2. This high density of actin filament binding sites on the cytoplasmic surface of a coated pit may favor multivalent binding of short filaments."
Entered by Uri M
ID 111113