Sandbox GGC2

Actin is a family of globular proteins that form microfilaments. It is the most abundant protein in eukaryotes ^[1]. They can be found in virtually all eukaryotic cells and come in two main forms, F-actin and G actin. Actin is responsible for many contraction properties in muscles.

Vertebrates have 3 main groups of actin isoforms, alpha, beta, and gamma. Alpha actins play a major role in muscle contraction mechanism. Beta and gamma actins are involved in the regulation of cell motility. Actin has the capability to bind with other molecules, most notably myosin and ATP, in order to carry out its function.

Function

Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells. The main function of ACTA1 gives directions to make the alpha (a)-actin. Actins are detrimental to cell movement and the contraction of muscle fibers. They are also used to help maintain the cytoskeleton. alpha skeletal actin is an essential component of sarcomeres, which are the basic contractile unit of muscle fibers.

Disease

Mutations in the human skeletal muscle alpha-actin gene (ACTA1) are associated with different muscle diseases, two of which are congenital myopathy, with an excess of thin myofilaments (actin myopathy), and nemaline myopathy. Both diseases can be identified by the abnormalities of the muscle fibers and variable degrees of muscle weakness^[2]. Congenital myopathies are a group of genetic muscle disorders that are identified with muscle weakness. Myopathy, congenital, with fiber-type disproportion (CFTD) is a genetically heterogeneous disorder in which there is relative hypotrophy of type 1 muscle fibers compared to type 2 fibers on skeletal muscle biopsy. However, these findings are not specific and can be found in many different myopathic and neuropathic conditions ^[3]. Another type of mutation is in the form of actin-accumulation myopathy. This type of mutation usually changes a single amino acid. These mutations can alter the way actin binds to ATP. This is problematic as ATP provides energy for cells and is used during thin filament formation, leading to impaired muscle contractions and weakened muscles. Cap myopathy is a form of missense mutation seen in the ACTA1 gene. It is a disorder that acts on skeletal muscles. Those diagnosed with it are familiar with muscles that have been weakened and are poor in tone. The mutation replaces methionine with valine. It can be identified by cap-like structures that are made of disorganized thin filaments, leading to impaired muscle contraction and muscle weakness.

Relevance

The ACTA1 protein is a key component in various structures. One is its involvement in the actin cytoskeleton, which is a network of actin and its binding proteins that work together with microtubules and intermediate filaments that regular functions like cell migration ^[4]. ACTA1 is also associated with the stress fiber, a contractile actin bundle of actin filaments made of short actin filaments with alternating polarities. The skeletal alpha-actin expression is induced by stimuli and conditions known to cause muscle formation.

Structural highlights

This is a sample scene created with SAT to by Group, and another to make of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes. One of the unique ligands is .