Stains
Actin - general
Copyright: 2003-2019, PathologyOutlines.com, Inc.
PubMed Search: actin[title]
Actin - general
Author: Nat Pernick, M.D.
Topic Completed: 1 September 2013
Minor changes: 15 December 2019
Copyright: 2003-2019, PathologyOutlines.com, Inc.
PubMed Search: actin[title]
Table of Contents
Definition / general | Pathophysiology | Clinical features | Diagrams / tables | Microscopic (histologic) imagesCite this page: Pernick, N. Actin - general. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsactin.html. Accessed August 3rd, 2020.
Definition / general
- Globular protein that forms microfilaments; found in all eukaryotic cells except nematode sperm (Wikipedia)
- Highly conserved, differs by at most 20% between algae and humans
- Participates in more protein-protein interactions than any known protein
Pathophysiology
- The monomeric subunit of microfilaments, one of 3 major components of cytoskeleton (also microtubules and intermediate filaments); also a component of thin filaments (part of contractile apparatus of muscle cells)
- Can transition between monomeric (G-actin) and filamentous (F-actin) states under control of nucleotide hydrolysis, ions, and actin-binding proteins (Annu Rev Biophys 2011;40:169)
- Mammalian muscle cells contain alpha and gamma smooth muscle actin, alpha cardiac actin and alpha skeletal actin
- Mammalian nonmuscle cells contain beta cytoplasmic actin and gamma cytoplasmic actin
- Functions in all cells:
- Forms part of cytoskeleton, which gives mechanical support to cell and is part of signal transduction
- Assists with motility and phagocytosis
- Helps myosins transport organelles and other substances through cell
- Actin cytoskeleton may act as sensor and mediator of apoptosis (Bioarchitecture 2012;2:75)
- Function in muscle cells: contraction
- Actin cap: recently characterized cytoskeletal organelle composed of thick and highly contractile acto-myosin filaments anchored to apical surface of interphase nucleus (Soft Matter 2013;9:5516)
Clinical features
- Persistence of high titers of anti-actin serum antibodies is associated with disease activity in autoimmune hepatitis (Hepatology 2013;59:592)
Diagrams / tables
Images hosted on other servers:
Actin and myosin in muscle
Helical structure of F-actin
G-actin to F-actin transition
Animation of muscle contraction
Microscopic (histologic) images
Various images
