Actin filaments

Actin filaments are the thinnest of the three comonents of cytoskeleton in respect to its diameter and thus the most flexible. It is required for the movement on the surface of the cells and also to maintain the shape of the cell. They are found in cells such as microvilli, filopodia and contractile bundles, plasma memberane and also in muscle cells.

Actin filament is a polymer made by polymerisation of actin monomers by hydrolysis of ATP. The filament is polarised and the monomers are more readily added to the positive side of the filament. And polymerisation is also regulated by different set of binding proteins such as bundle protein, cross linked protein, motor proteins etc.

The actin filament's motor proteins are the myosin. Myosin have a head and a tail, the head binds to the actin filament and the tail is bound to plasma meberane, vesicles and other yosin proteins. The hydrolysis of ATP drives the myosin resulting in movement.

Myosin is further divided into myosin 1 and myosin 2.