Characterisation of the F-actin binding domains of villin: classification of F-actin binding proteins into two groups according to their binding sites on actin.
The F-actin binding properties of chicken villin, its headpiece and domains 2-3 (V2-3) have been analysed to identify sites involved in bundle formation. Headpiece and V2-3 bind actin with Kd values of approximately 7 microM and approximately 0.3 microM, respectively, at low ionic strength. V2-3 binding, like that of villin, is weakened with increasing salt concentration; headpiece binding is not. Competition experiments show that headpiece and V2-3 bind to different sites on actin, forming the two cross-linking sites of villin. Headpiece does not compete with the F-actin binding domains of gelsolin or alpha-actinin, but it dissociates actin depolymerizing factor. We suggest that the F-actin binding domains of actin severing, crosslinking and capping proteins can be organized into two classes.
Pope
B
B
MRC Laboratory of Molecular Biology, Cambridge, UK.
Way
M
M
Matsudaira
P T
PT
Weeds
A
A
D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism*; D002645:Chickens; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008840:Microfilament Proteins / Q000145:classification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009994:Osmolar Concentration
D000199:Actins; D002352:Carrier Proteins; D008840:Microfilament Proteins; C026615:villin