Lecture 3

Actin Dynamics

The dynamic assembly and disassembly of actin filaments essential for cellular processes.

Arp2/3 Complex

A complex found in all eukaryotes that leads to branching of actin filaments.

Nucleation Promoting Factors (NPFs)

Accessory proteins that enhance the activity of the Arp2/3 complex.

WASp

An activating protein that helps bind G-actin to the Arp2/3 complex, enabling actin filament nucleation.

Phagocytosis

The process where cells engulf materials through actin filament dynamics.

Formins

A diverse family of proteins that nucleate unbranched actin filaments.

Cofilin

A protein that enhances actin depolymerization at the (-) end, recycling actin.

Fimbrin

An actin cross-linker that arranges filaments into tight bundles with the same polarity.

α-actinin

An actin cross-linker that holds filaments in rigid rods with more spacing.

Spectrin

A tetrameric protein that spans greater distances between actin filaments.

Filamin

A cross-linker that enables stabilizing cross-links between actin filaments in networks.

ActA

A Listeria protein that activates the Arp2/3 complex for actin nucleation.