Alpha-actinin-3
mammalian protein found in Homo sapiens
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 (named sprinter gene, speed gene or athlete gene) located on chromosome 11. All people have two copies (alleles) of this gene.
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.
Fast versus slow twitch muscle fibers
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.
“Alpha-actinin-3” enters the record as mammalian protein found in Homo sapiens. Crown Archives preserves that source wording while asking what Alpha-actinin-3, mammalian and protein can confirm, complicate or overturn.
Why this record matters
“Alpha-actinin-3” is worth following because a concise public description often conceals a longer documentary argument. Here, Alpha-actinin-3, mammalian and protein provides the most credible route into that argument.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 13, 2026. The linked authority identifier is Q21096435.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Alpha-actinin-3”, its source revision and the description used here.
- Expand the search: follow Alpha-actinin-3 primary sources, Alpha-actinin-3 archive and Alpha-actinin-3 research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Alpha-actinin-3”?
- What terminology or title could unlock a more precise catalogue search?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Alpha-actinin-3” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.