Regulation of Microtubule and Actin Filament Dynamics

Regulation of Filament Dynamics (Overview)

three types of proteins that regulate filament dynamics,

• bind to filament ends, either plus or minus end,

• bind to filament sides

• bind to free subunits.

Proteins that Bind to Filament Ends

can block subunit edition at either plus or minus end, called capping,

can also stimulate addition of subunits at ends, including nucleation.

can facilitate filament disassembly & regulate nucleotide hydrolysis by sub units that are at end of filaments.

Proteins that Bind to Filament Ends 1

block subunit addition at either plus or minus end, called capping,

Proteins that Bind to Filament Ends 2

can also stimulate addition of subunits at ends, including nucleation.

Proteins that Bind to Filament Ends 3

can facilitate filament disassembly & regulate nucleotide hydrolysis by sub units at end of filaments.

Proteins that Bind to Filament Sides

1. can sever filaments, important for rapid reorganization of filaments.

2. can stabilize filaments

Proteins that Bind to Free Subunits

1. can block assembly of these subunits with growing filament

2. can promote assembly of subunits into a growing filament.

3. can also regulate the nucleotide exchange of subunits.

Summary of Regulation of Filament Dynamics

In summary, proteins can regulate filament dynamics by binding to filament ends. Filament sides or free subunits, proteins that bind to the filament ends can promote or prevent dynamics, and proteins that bind to the filament sides can sever or stabilize filaments, proteins that bind to free sub units can promote or prevent filament assembl