Villin-type headpiece domains show a wide range of F-actin-binding affinities
Department of Cell Biology
Actins; Amino Acid Sequence; Animals; Carrier Proteins; Chickens; Chromatography, Gel; Circular Dichroism; Cytoskeleton; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Kinetics; Microfilament Proteins; Models, Molecular; Molecular Sequence Data; Plasmids; Protein Binding; Protein Conformation; Protein Folding; Protein Structure, Tertiary; Recombinant Proteins; Sequence Homology, Amino Acid; Software; Temperature; Ultraviolet Rays
Cell Biology | Life Sciences | Medicine and Health Sciences
The villin-type "headpiece" domain is a modular motif found at the extreme C-terminus of larger "core" domains in over 25 cytoskeletal proteins in plants and animals. Although headpiece is classified as an F-actin-binding domain, it has been suggested that some expressed fusion-proteins containing headpiece may lack F-actin-binding in vivo. To determine the intrinsic F-actin affinity of headpiece domains, we quantified the F-actin affinity of seven headpiece domains and three N-terminal truncations, under identical in vitro conditions. The constructs are folded and adopt the native headpiece structure. However, they show a wide range of affinities that can be grouped into high, low, and nonspecific-binding categories. Computer models of the structure and charged surface potential of these headpiece domains suggest features important for high F-actin affinity. We conclude that not all headpiece domains are intrinsically F-actin-binding motifs, and suggest that the surface charge distribution may be an important element for F-actin recognition.
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Citation: Cell Motil Cytoskeleton. 2002 May;52(1):9-21. Link to article on publisher's site