Actin

Actin is a globular protein that polymerizes helically forming actin filaments (or microfilaments), which like the other two components of the cellular cytoskeleton form a three-dimensional network inside an eukaryotic cell. Actin filaments provide mechanical support for the cell, determine the cell shape, enable cell movements (through lamellipodia or pseudopodia); and participate in certain cell junctions, in cytoplasmic streaming and in contraction of the cell during cytokinesis. In muscle cells they play an essential role, along with myosin, in muscle contraction. In the cytosol, actin is predominantly bound to ATP, but can also bind to ADP. An ATP-actin complex polymerizes faster and dissociates slower than an ADP-actin complex. Actin is also one of the most highly conserved proteins, differing by no more than 5% in species as diverse as algae and humans.

Related Topics:
Protein - Polymerizes - Cytoskeleton - Eukaryotic - Cell - Lamellipodia - Pseudopodia - Cytoplasmic streaming - Cytokinesis - Muscle cell - Myosin - Muscle contraction - Cytosol - ATP - ADP

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