Dissociation of cytosolic complex leads to the stabilization of the full-length Ci, which moves into the

nucleus, displaces the repressor Ci75 from the promoter of target genes, and induces expression of target genes.

TLS Online TPP Program

#Id: 8330

#XL - Q Biochemistry

TLS Online TPP Program

#Id: 8329

#XL - Q Biochemistry

Treadmilling

Because the critical concentrations for the two ends are different, at steady state the free ATP–G-actin will be intermediate between Cc+ and Cc - , so the (+)end will grow and the (-)end will lose subunits.

TLS Online TPP Program

#Id: 8327

#XL - Q Biochemistry

TLS Online TPP Program

#Id: 8326

#XL - Q Biochemistry

The two ends of microfilament polymerize at different rates:

fast-growing end - plus end

slow-growing end - minus end

TLS Online TPP Program

#Id: 8325

#XL - Q Biochemistry

Critical concentration (Cc)

minimal concentration of monomers at which filaments form

TLS Online TPP Program

#Id: 8324

#XL - Q Biochemistry

The rate of addition of monomers is given by

rate constant kon (M–1 sec–1 )

The rate of loss is given by koff (sec–1)