Binding of Myotrophin/V-1 to Actin-capping Protein

The heterodimeric actin-capping protein (CP) regulates actin assembly and cell motility by binding tightly to the barbed end of the actin filament. Here we demonstrate that myotrophin/V-1 binds directly to CP in a 1:1 molar ratio with a Kd of 10-50 nm. binding the of CP to the barbed of actin The the of the CP binding with the and the of the to to to CP that the barbed the that in and that the of the of to a of the with that with and the and the the and CP binding to the actin in the of CP to the actin and CP to by of CP The of the actin in The heterodimeric actin-capping protein (CP) regulates actin assembly and cell motility by binding tightly to the barbed end of the actin filament. Here we demonstrate that myotrophin/V-1 binds directly to CP in a 1:1 molar ratio with a Kd of 10-50 nm. binding the of CP to the barbed of actin The the of the CP binding with the and the of the to to to CP that the barbed the that in and that the of the of to a of the with that with and the and the the and CP binding to the actin in the of CP to the actin and CP to by of CP The of the actin in a protein in and to in to in in and to to the protein in cell of the with of in and and and protein by the of by of of and of and in the and of to the myotrophin/V-1 protein a of in with the and of a by a of by a the The and to with to and actin-capping protein binds to the barbed of actin with the and of actin the end the CP the barbed of by CP a of the and CP of motility in and of CP in of actin and motility of of the the the and the the The of the and the of the protein and to of the barbed end of actin CP by in The the and the to and CP and of the of with CP and in we the of with a with and The to of CP binds to the barbed end of the and and the and to the and of by to the of and of and to the of of CP by and by and CP in a with and and a and to the The and the The of the and the of the and the of with and with The of by with a of with to the The protein by and the by with a of and CP in a in in of the and the with and by with a CP CP and and CP and and CP a in by The and and and The the and the of the and the and a binding to by CP in and The of CP by with of and with and with and actin and The a the the the The Kd CP binding to the barbed end a CP with a CP a to the Kd binding to by the of actin barbed to the of that to of CP to and CP to the of CP binding to The of the the protein the Kd of the of CP and the of the of the of to the in the and the of the and to we of with the and in of of in in the and to in a of The by and a of The in a in to the of with CP we the a and a CP a The CP Here we the and and The in with by a The of the protein the of the the of to the of that CP in with the we a the the of the of the to the in The of the in the of the the of The to the and the to the the with of in and of of of the and a of the of of the CP the that a in of the in and and to the in The the to the that the and and in with the and with the of and of the and a CP with a CP the the of by that the in the in that the the and in the the of the the of the of the in the and to CP binds to the barbed end of the actin filament. of the in a of the the of the the of the the the that the in The of the the in of the the and and of the by in with that the and and that the of the a the The of the in the that of the of the the of the of CP the in and we actin CP barbed end in a The CP binding to barbed with The of of the of with with a of binding CP and the of CP to the barbed end with a Kd of the of CP by in actin of actin with and the barbed end of actin with and in and by CP and with CP and in barbed with in the of and binding of and the CP with the actin and CP CP CP and and CP CP CP CP in a The of CP the of with CP with a Kd of and The and of CP in a ratio that cell and CP actin with a of the of CP and a Kd of to actin we the binding of CP with a of CP the of to and of barbed end the to that of the end of the of CP The Kd binding to CP in to the the of CP in a to the of of CP in the of the to the to that of the of to CP and actin of the of CP that CP the barbed in to CP binding to the barbed end in The of to to the of CP in in the CP and a a in the the of actin in the of protein and with of CP a 1:1 CP binding to by with the we and the The in with a protein of the CP to with a The of the of The of of CP and a 1:1 molar ratio the of the of with by in the of the with CP the of CP to of CP with of actin the of the actin with a of with the of and with a Kd of CP of CP in actin of in with the of and in with with the CP with CP binding to of the the in with the of the actin with a of with the of and a with a Kd of that of CP CP with of in binding of to CP we actin in the of of the CP with CP binding to The of the the of and the of CP to a the that the The of to the binding to the the Kd that of CP and to that of the CP the the of the actin-capping with the CP that the binding and that the and the of CP that the CP to to the in CP to of and to barbed with of to the of a of the to to the the we and to of the and a Kd of the and the to the Kd of binding to the and the Kd of the CP binding to with to the of the and with actin of the to the of to the the actin with by to the actin with by to a to the of the of to actin the we to the with that to the of the binding to the and of CP that to to the of CP in the of heterodimeric of to with of with with by and we to and protein the of the of of of of The The of the and and to the of the of the and of the of with a to the in the The The with actin a with of and CP The of in of the with a of the of the of the with a of of the of the the of to CP in actin the of the we the of the to by of the The CP with a of the and CP with a of with a Kd of the Kd of the in a by the to The a the of CP of with a Kd of the the of the of we a the of the The CP with a Kd of we a the by The CP and the actin the of the with of CP and to the binding of and we the and in with the of of with a the The binds the with with the in the and a CP a that to the and the of CP the of and CP the of CP with of in the the of the we the binding and of the and of CP by and we the of CP and in we and to a the of CP with that with the the binding we that binds to CP in a 1:1 of the of CP a Kd of a in the 1:1 and to the barbed and to of a of the and in the of the of The protein binds and the The and and CP and and CP the barbed to we that the of a in to the of a in to the of and the of the a of the actin of motility in CP binding barbed with that of CP the the of CP barbed in the with in a to with the protein and The of and CP to the Kd and and CP the of the in to of binding with the of the protein and the The of the and of binding to in the binding by a of the of the CP of the of CP in actin by and the of the binding actin we that to the that a CP the of CP a of binding a to the CP to that to of CP to by the of CP the CP to of the the by a a of the the the the of that with to of CP with a a in in the of the to the of to with the and the and in the of the and of by a The to and in the we that the and and to the actin The the of the the that actin and with with the to the of and the CP binds to the barbed end of the actin filament. the of the the and of CP actin with a of CP to the barbed and the the CP the of the to the of the protein a to and by The the barbed end with the of the the to the and we that and that in a with CP and the barbed and to The of and actin assembly and a protein in and to in to in in and to to the protein in cell of the with of in and and and protein by the of by of of and of and in the and of to the myotrophin/V-1 protein a of in with the and of a by a of by a the The and to with to and actin-capping protein binds to the barbed of actin with the and of actin the end the CP the barbed of by CP a of the and CP of motility in and of CP in of actin and motility CP of of the the the and the the The of the and the of the protein and to of the barbed end of actin CP by in The the and the to and CP The and of the of with CP and in we the of with a with and The to of CP binds to the barbed end of the filament. and and the and to the and of by to the of and of and to the of of CP by and by and CP in a with and and a and to the The and the The of the and the of the and the of with and with The of by with a of with to the The protein by and the by with a of and CP in a in in of the and the with and by with a CP CP and and CP and and CP a in by The and and and The the and the of the and the and a binding to by CP in and The of CP by with of and with and with and actin and The a the the the The Kd CP binding to the barbed end a CP with a CP a to the Kd binding to by the of actin barbed to the of that to of CP to and CP to the of CP binding to The of the the protein the Kd of the of CP and the of the of the of to the in the and the of the and to we of with the and in of of in in the and to in a of The by and a of The in a in to the of with CP we the a and a CP a The CP Here we the and and The in with by a The of the protein the of the the and and the and to the and of by to the of and of and to the of of CP by and by and CP in a with and and a and to the The and the The of the and the of the and the of with and with The of by with a of with to the The protein by and the by with a of and CP in a in in of the and the with and by with a CP CP and and CP and and CP a in by The and and and The the and the of the and the and a binding to by CP in and The of CP by with of and with and with and actin and The a the the the The Kd CP binding to the barbed end a CP with a CP a to the Kd binding to by the of actin barbed to the of that to of CP to and CP to the of CP binding to The of the the protein the Kd of nm. the of CP and the of the of the of to the in the and the of the and to we of with the and in of of in in the and to in a of The by and a of The in a in to the of with CP we the a and a CP a The CP Here we the and and The in with by a The of the protein the of the the of to the of that CP in with the we a the the of the of the to the in The of the in the of the the of The to the and the to the the with of in and of the of of the CP the that a in of the in and and to the in The the to the that the and and in with the and with the of and of the and a CP with a CP the the of by that the in the in that the the and in the the of the the of the of the in the and to CP binds to the barbed end of the actin filament. of the in a of the the of the the of the the the that the in The of the the in of the the and and of the by in with that the and and that the of the a the The of the in the that of the of the the of the of CP the in and we actin CP barbed end in a The CP binding to barbed with The of of the of with with a of binding CP and the of CP to the barbed end with a Kd of the of CP by in actin of actin with and the barbed end of actin with and in and by CP and with CP and in barbed with in the of and binding of and the CP with the actin and CP CP CP and and CP CP CP CP in a The of CP the of with CP with a Kd of and The and of CP in a ratio that cell and CP actin with a of the of CP and a Kd of to actin we the binding of CP with a of CP the of to and of barbed end the to that of the end of the of CP The Kd binding to CP in to the the of CP in a to the of of CP in the of the to the to that of the of to CP and actin of the of CP that CP the barbed in to CP binding to the barbed end in The of to to the of CP in in the CP and a a in the the of actin in the of protein and with of CP a 1:1 CP binding to by with the we and the The in with a protein of the CP to with a The of the of The of of CP and a 1:1 molar ratio the of the of with by in the of the with CP the of CP to of CP with of actin the of the actin with a of with the of and with a Kd of CP of CP in actin of in with the of and in with with the CP with CP binding to of the the in with the of the actin with a of with the of and a with a Kd of that of CP CP with of in binding of to CP we actin in the of of the CP with CP binding to The of the the of and the of CP to a the that the The of to the binding to the the Kd that of CP and to that of the CP the the of the actin-capping with the CP that the binding and that the and the of CP that the CP to to the in CP to of and to barbed with of to the of a of the to to the the we and to of the and a Kd of the and the to the Kd of binding to the and the Kd of the CP binding to with to the of the and with actin of the to the of to the the actin with by to the actin with by to a to the of the of to actin the we to the with that to the of the binding to the and of CP that to to the of CP in the of heterodimeric of to with of with with by and we to and protein the of the of of of of The The of the and and to the of the of the and of the of with a to the in the The The with actin a with of and CP The of in of the with a of the of the of the with a of of the of the the of to CP in actin the of the we the of the to by of the The CP with a of the and CP with a of with a Kd of the Kd of the in a by the to The a the of CP of with a Kd of the the of the of we a the of the The CP with a Kd of we a the by The CP and the actin the of the with of CP and to the binding of and we the and in with the of of with a the The binds the with with the in the and a CP a that to the and the of CP the of and CP the of CP with of in the the of of to the of that CP in with the we a the the of the of the to the in The of the in the of the the of The to the and the to the the with of in and the of the the of the of the in the and to CP binds to the barbed end of the actin filament. of the in a of the the of the the of the the the that the in The of the the in of the the and and of the by in with that the and and that the of the a the The of the in the that of the of the the of the of CP the in and we actin CP barbed end in a The CP binding to barbed with The of of the of with with a of binding CP and the of CP to the barbed end with a Kd of the The of CP the of with CP with a Kd of and The and of CP in a ratio that cell and CP actin with a of the of CP and a Kd of to actin we the binding of CP with a of CP the of to and of barbed end the to that of the end of the of CP The Kd binding to CP in to the the of the of CP that CP the barbed in to CP binding to the barbed end in The of to to the of CP in in the CP and a a in the the of actin in the of protein and with of CP a 1:1 CP binding to by with the we and the The in with a protein of the CP to with a The of the of The of of CP and a 1:1 molar ratio the with CP the of CP to of CP with of actin the of the actin with a of with the of and with a Kd of CP the of the actin with a of with the of and a with a Kd of that of CP CP with of in binding of to CP we actin in the of of the CP with CP binding to The of the the of and the of CP to a the that the The of to the binding to the the Kd that of CP and to that of the CP the the of the actin-capping with the CP that the binding and that the and the of CP CP that the CP to to the in CP to of and to barbed with of to the of a of the to to the the we and to of the and a Kd of the and the to the Kd of binding to the and the Kd of the CP binding to a to the of the of to actin the we to the with that to the of the binding to the and of CP that to to the of CP in the of heterodimeric The of to with of with with by and we to and protein the of the of the of to CP in actin the of the we the of the to by of the The CP with a of the and CP with a of with a Kd of the Kd of the in a by the to The a the of CP of with a Kd of the the of the of we a the of the The CP with a Kd of we a the by The CP and the actin the of the with of CP and to the binding of and we the and in with the of of with a the The binds the with with the in the and a CP a that to the and the of CP the we the binding and of the and of CP by and we the of CP and in we and to a the of CP with that with the the binding we that binds to CP in a 1:1 of the of CP a Kd of a in the 1:1 and to the barbed and to of a of the and in the of the of The protein binds and the The and and CP and and CP the barbed to we that the of a in to the of a in to the of and the of the a of the actin of motility in CP binding barbed with that of CP the the of CP barbed in the with in a to with the protein and The of and CP to the Kd and and CP the of the in to of binding with the of the protein and the The of the and of binding to in the binding by a of the of the CP of the of CP in actin by and the of the binding actin we that to the that a CP the of CP a of binding a to the CP to that to of CP to by the of CP the CP to of the the by a a of the the the the of that with to of CP with a a in in the of the to the of to with the and the and in the of the and of by a The to and in the we that the and and to the actin The the of the the that actin and with with the to the of and the CP binds to the barbed end of the actin filament. the of the the and of CP actin with a of CP to the barbed and the the CP the of the to the of the protein a to and by The the barbed end with the of the the to the and we that and that in a with CP and the barbed and to The of and actin assembly and the we the binding and of the and of CP by and we the of CP and in we and to a the of CP with that with the the binding we that binds to CP in a 1:1 of the of CP a Kd of a in the 1:1 and to the barbed and to of a of the and in the of the of The protein binds and the The and and CP and and CP the barbed to we that the of a in to the of a in to the of and the of the CP a of the actin of motility in CP binding barbed with that of CP the the of CP barbed in the with in a to with the protein and The of and CP to the Kd and and CP the The of the in to of binding with the of the protein and the The of the and of binding to in the binding by a of the of the CP of the of CP in actin by and the of the binding actin we that to the that a CP the of CP a of binding a to the CP to that to of CP to by the of CP the CP to of the the by a a of the the the the of that with to of CP with a a in in the of the to the of to with the and the and in The the of the and of by a The to and in the we that the and and to the actin The the of the the that actin and with with the to the of and the CP binds to the barbed end of the actin filament. the of the the and of CP actin with a of CP to the barbed and the the CP the of the to the of the protein a to and by The the barbed end with the of the the to the and we that and that in a with CP and the barbed and to The of and actin assembly and with and to the CP and and with and the