A Llama-Derived Gelsolin Single-Domain Antibody Blocks Gelsolin-G-Actin Interaction.
Van Den Abbeele, A., De Clercq, S., De Ganck, A., De Corte, V., Van Loo, B., Soror, S.H., Srinivasan, V., Steyaert, J., Vandekerckhove, J., Gettemans, J.(2010) Cell Mol Life Sci 67: 1519
- PubMed: 20140750 
- DOI: https://doi.org/10.1007/s00018-010-0266-1
- Primary Citation of Related Structures:  
2X1O, 2X1P, 2X1Q - PubMed Abstract: 
RNA interference has tremendously advanced our understanding of gene function but recent reports have exposed undesirable side-effects. Recombinant Camelid single-domain antibodies (VHHs) provide an attractive means for studying protein function without affecting gene expression. We raised VHHs against gelsolin (GsnVHHs), a multifunctional actin-binding protein that controls cellular actin organization and migration. GsnVHH-induced delocalization of gelsolin to mitochondria or the nucleus in mammalian cells reveals distinct subpopulations including free gelsolin and actin-bound gelsolin complexes. GsnVHH 13 specifically recognizes Ca(2+)-activated gelsolin (K (d) approximately 10 nM) while GsnVHH 11 binds gelsolin irrespective of Ca(2+) (K (d) approximately 5 nM) but completely blocks its interaction with G-actin. Both GsnVHHs trace gelsolin in membrane ruffles of EGF-stimulated MCF-7 cells and delay cell migration without affecting F-actin severing/capping or actin nucleation activities by gelsolin. We conclude that VHHs represent a potent way of blocking structural proteins and that actin nucleation by gelsolin is more complex than previously anticipated.
Organizational Affiliation: 
Department of Medical Protein Research, VIB, 9000 Ghent, Belgium.