Villin-type headpiece domains show a wide range of F-actin-binding affinities.
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.
Vardar
D
D
Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
Chishti
A H
AH
Frank
B S
BS
Luna
E J
EJ
Noegel
A A
AA
Oh
S W
SW
Schleicher
M
M
McKnight
C J
CJ
D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry*; D002645:Chickens; D002850:Chromatography, Gel; D002942:Circular Dichroism; D003599:Cytoskeleton / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008840:Microfilament Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012984:Software; D013696:Temperature; D014466:Ultraviolet Rays
D000199:Actins; D002352:Carrier Proteins; D008840:Microfilament Proteins; D011994:Recombinant Proteins; C026615:villin