BIOL 201 Lecture Notes - Lecture 28: Actomyosin Ring, Depolymerization, Microtubule
27 Nov 2015
School
Department
Course
Professor
Document Summary
Depolymerization of microtubules stops migration in the scratch assay. Colchicum autmnale hinders movement by binding to microtubules and sequesters it into an inactive state. Microtubules will undergo catastrophe and will collapse. Without microtubules, lamellopodia extend but go nowhere: colcemid causes lamellopodia to extend but no movement. Microtubule depolymerization in non-migrating cells induces stress fibres. Absence of microtubules triggers cytoskeleton to form stress fibres. Microtubules alter the activation state of rho family gtpases: microtubules must activate rac and inhibit rho, the rac is responsible for nucleation of dendritic networks by the arp2/3 complex. pioneer microtubules penetrate into the lamellopodia and filopodia: growing microtubules somehow activate rac. There must be a rac gef that senses a growing microtubule and turns rac into an on- state: microtubules sequester and inactivate a rho-gef. Dynein is on the cortex and pulls on the microtubules. Nucleus is on the back end of the cell and centrosomes are towards the front.
