Cytoskeleton Dynamics: Actin and Microtubules

Cytoskeleton

Dynamic protein fiber system for support and movement.

Microtubules

25 nm protein fibers, part of cytoskeleton.

Microfilaments

7 nm protein fibers, composed of actin.

Intermediate Filaments

8-12 nm fibers providing structural support.

Actin Monomers

Globular proteins that polymerize to form filaments.

G Protein

Protein with nucleotide binding site for ATP/ADP.

Nucleation

Initial step of actin polymerization, forming dimers.

F-Actin

Filamentous form of actin, polymerized structure.

Polymerization

Process of actin monomers forming long chains.

Depolymerization

Breakdown of actin filaments, favored at minus end.

Actin Binding Proteins (ABPs)

Proteins that regulate actin filament dynamics.

Actin Bundles

Tightly packed actin filaments, increase surface area.

Terminal Web

Network of actin filaments beneath cell membrane.

Myosin

Motor protein converting ATP to mechanical energy.

Cytokinesis

Division of cytoplasm using actin and myosin.

Vesicle Transport

Movement of vesicles along actin filaments.

Microtubules

Hollow tubes made of tubulin, 13 protofilaments.

Tubulin

Dimer of alpha and beta tubulin forming microtubules.

GTP Cap

Stabilizing state of tubulin preventing depolymerization.

Dynamic Instability

Rapid growth and shrinkage of microtubules.

Centrosome

Microtubule organizing center with centrioles.

Kinesin

Motor protein moving toward plus end of microtubules.

Dynein

Motor protein moving toward minus end of microtubules.

Axoneme

Structure of cilia and flagella, '9 + 2' arrangement.

Cell Theory

All living organisms consist of one or more cells.

Eukaryotic Cell Cycle

Growth, DNA replication, and cell division phases.