Actinin alpha 3

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ACTN3
Protein ACTN3 PDB 1tjt.png
Available structures
PDBHuman UniProt search: PDBe RCSB
Identifiers
AliasesACTN3, actinin alpha 3 (gene/pseudogene), ACTN3D, actinin alpha 3
External IDsOMIM: 102574 GeneCards: ACTN3
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001104
NM_001258371

n/a

RefSeq (protein)

NP_001095
NP_001245300

n/a

Location (UCSC)Chr 11: 66.55 – 66.56 Mbn/a
PubMed search[2]n/a
Wikidata
View/Edit Human

Alpha-actinin-3, also known as alpha-actinin skeletal muscle isoform 3 or F-actin cross-linking protein, is a protein that in humans is encoded by the ACTN3 gene.[3][4]

Alpha-actinin is an actin-binding protein with multiple roles in different cell types. This gene expression is limited to skeletal muscle. It is localized to the Z-disc and analogous dense bodies, where it helps to anchor the myofibrillar actin filaments.[3]

Fast versus slow twitch muscle fibers[edit]

Skeletal muscle is composed of long cylindrical cells called muscle fibers. There are two types of muscle fibers, slow twitch or muscle contraction (type I) and fast twitch (type II). Slow twitch fibers are more efficient in using oxygen to generate energy, while fast twitch fibers are less efficient. However, fast twitch fibers fire more rapidly, allowing them to generate more power than slow twitch (type I) fibers. Fast twitch fibers and slow twitch fibers are also called white muscle fibers and red muscles fibers, respectively.

Alleles[edit]

An allele (rs1815739; R577X) has been identified in the ACTN3 gene which results in a deficiency of alpha-actinin 3 in a significant proportion of the population.[5][6] The X homozygous genotype is caused by a C to T transition in exon 16 of the ACTN3 gene, which causes a transformation of an arginine base (R) to a premature stop codon (X) resulting in the rs1815739 mutation causing no production of the alpha-actinin 3 protein in muscle fibers.[7] The 577XX polymorphism causes no production of alpha-actinin 3 protein which is essential in fast twitch muscle fibers.[7]

It has been speculated that variations in this gene evolved to accommodate the energy expenditure requirements of people in various parts of the world.[5]:155–156

Athletes[edit]

There is an association between the ACTN3 R577X polymorphism in sprint and powerlifting performance at an elite level, and appears to be an association with exercise recovery and lower injury risk.[7] It appears that the XX genotype is associated with higher levels of muscle damage and a longer time required for recovery.[7]

Interactions[edit]

ACTN3 has been shown to interact with Actinin, alpha 2.[8]

See also[edit]

References[edit]

  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000248746 - Ensembl, May 2017
  2. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  3. ^ a b "Entrez Gene: ACTN3 actinin, alpha 3".
  4. ^ Beggs AH, Byers TJ, Knoll JH, Boyce FM, Bruns GA, Kunkel LM (May 1992). "Cloning and characterization of two human skeletal muscle alpha-actinin genes located on chromosomes 1 and 11". The Journal of Biological Chemistry. 267 (13): 9281–8. doi:10.1016/S0021-9258(19)50420-3. PMID 1339456.[permanent dead link]
  5. ^ a b David Epstein. The Sports Gene: Inside the Science of Extraordinary Athletic Performance. ISBN 9781101622636
  6. ^ North KN, Yang N, Wattanasirichaigoon D, Mills M, Easteal S, Beggs AH (April 1999). "A common nonsense mutation results in alpha-actinin-3 deficiency in the general population". Nature Genetics. 21 (4): 353–4. doi:10.1038/7675. PMID 10192379. S2CID 19882092.
  7. ^ a b c d Pickering C, Kiely J (2017). "ACTN3: More than Just a Gene for Speed". Frontiers in Physiology. 8: 1080. doi:10.3389/fphys.2017.01080. PMC 5741991. PMID 29326606.
  8. ^ Chan Y, Tong HQ, Beggs AH, Kunkel LM (July 1998). "Human skeletal muscle-specific alpha-actinin-2 and -3 isoforms form homodimers and heterodimers in vitro and in vivo". Biochemical and Biophysical Research Communications. 248 (1): 134–9. doi:10.1006/bbrc.1998.8920. PMID 9675099.

Further reading[edit]

External links[edit]