Stains & CD markers
Actin - general / cardiac
Copyright: 2003-2023, PathologyOutlines.com, Inc.
PubMed Search: Actin
Actin - general / cardiac
Author: Nat Pernick, M.D.
Last author update: 1 September 2013
Last staff update: 5 July 2022
Copyright: 2003-2023, PathologyOutlines.com, Inc.
PubMed Search: Actin
Table of Contents
Definition / general | Pathophysiology | Clinical features | Alpha cardiac actin | Diagrams / tables | Microscopic (histologic) imagesCite this page: Pernick, N. Actin - general / cardiac. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsactin.html. Accessed February 8th, 2023.
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)
Alpha cardiac actin
- Also called ACTC1
- Two types of alpha sarcomeric / striated actin: alpha cardiac type and alpha skeletal muscle type; both are expressed in cardiac and skeletal muscle, but the proportions vary at different developmental periods (J Biol Chem 1994;269:12212) or with disease (Rapid Commun Mass Spectrom 2003;17:1467)
- Existence of two actin isoforms and their conformational differences may be part of tuning regulatory mechanism, by which the cardiac muscle cells can maintain their biological function under pathological conditions (Biochem Biophys Res Commun 2008;368:696)
- Mutations in alpha cardiac actin may cause dilated or hypertrophic cardiomyopathy (J Mol Cell Cardiol 2000;32:1687, J Biol Chem 2006;281:16777); location of mutations correlate with type of functional change (PLoS One 2012;7:e36821)
- Mutations may cause familial atrial septal defects (Hum Mol Genet 2008;17:256) due to reduced ACTC1 expression inducing cardiomyocyte apoptosis (Circ J 2010;74:2410)
Diagrams / tables
Images hosted on other servers:
Helical structure of F-actin
G-actin to F-actin transition
Microscopic (histologic) images
Images hosted on other servers:
Various images
