P10988 · ACT1_PLAFO

Function

function

Actin is a highly conserved protein that polymerizes to produce filaments that form cross-linked networks in the cytoplasm. Polymerizes into shorter and less stable actin filaments compared to ACT2/actin-2; this is thought to facilitate gliding motility and host cell invasion. Has ATPase activity. ATP hydrolysis leads to the formation of a stable intermediate ADP-inorganic phosphate (Pi) actin, which is followed by the release of Pi. ATP hydrolysis affects filament stability; ADP-bound actin depolymerizes much faster than ATP- or ADP-Pi-bound actin. Plays an essential role during the asexual blood stage. At the segmented schizont stage, required for apicoplast migration and segregation into individual daughter merozoites. Also, required for the separation of daughter merozoites in the final stages of cytokinesis. Essential for merozoite invasion of, but not adhesion to or reorientation towards, host erythrocytes.

Miscellaneous

A potassium ion appears to reside in the active site during hydrolysis and leaves together with the inorganic phosphate Pi. K+ does not activate Pi release; however, it may be relevant for ATP hydrolysis.
ACT1 and ACT2 differ in their polymerization, filament stability and helical structure. Unlike mammalian actin, Apicomplexa actins do not form long and stable filaments.

Catalytic activity

Activity regulation

ATP hydrolysis occurs in the polymeric state. Unlike for mammalian actin, ATP hydrolysis occurs also in the monomeric form and the release of inorganic phosphate (Pi) is more efficient.

Features

Showing features for binding site.

TypeIDPosition(s)Description
Binding site15ATP (UniProtKB | ChEBI)
Binding site16ATP (UniProtKB | ChEBI)
Binding site17ATP (UniProtKB | ChEBI)
Binding site19ATP (UniProtKB | ChEBI)
Binding site158ATP (UniProtKB | ChEBI)
Binding site159ATP (UniProtKB | ChEBI)
Binding site160ATP (UniProtKB | ChEBI)
Binding site214ATP (UniProtKB | ChEBI)
Binding site215ATP (UniProtKB | ChEBI)
Binding site303ATP (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentactin filament
Cellular Componentcytoplasm
Cellular Componentnucleus
Molecular FunctionATP binding
Molecular Functionhydrolase activity
Molecular Functionstructural constituent of cytoskeleton
Biological Processsymbiont-medited actin polymerization-dependent cell-to-cell migration in host

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Actin-1
  • EC number
  • Alternative names
    • Actin I
      (pf-actin I
      )

Gene names

    • Name
      ACT1
    • Synonyms
      ACTI

Organism names

Accessions

  • Primary accession
    P10988

Subcellular Location

Cytoplasm
Nucleus
Note: During host erythrocyte invasion, filamentous actin localizes close to the junction between merozoites and the host cell. In schizonts, filamentous actin appears to connect apicoplasts (By similarity).
Prior to gametocyte activation in the mosquito midgut, localizes to both the cytoplasm and the nucleus. Following gametocyte activation, relocalizes completely to the cytoplasm, in an ACT2-dependent manner (By similarity).

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00000889941-376Actin-1

Expression

Developmental stage

Actin-1 is formed in all parasitic stages; asexual blood stages and in the sexual stages. Actin-2 is stage-specific, formed only in the sexual stages of the parasite's life cycle.

Interaction

Subunit

Monomer (G-actin). Oligomer (F-actin). Polymerization of globular actin (G-actin) leads to a structural filament (F-actin) in the form of a two-stranded helix. Unlike for mammalian monomeric actin, parasite monomeric actin is able to induce oligomerization in the presence of ATP or ADP. Mg2+, which is used to coordinate ATP, is required for polymerization. Interacts with MyoA (By similarity).
Interacts with DNase I with low affinity (By similarity).

Structure

Family & Domains

Features

Showing features for region.

TypeIDPosition(s)Description
Region40-61DNAseI-binding D loop; regulates polymerization and stability of the actin filament

Sequence similarities

Belongs to the actin family.

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    376
  • Mass (Da)
    41,843
  • Last updated
    1989-07-01 v1
  • Checksum
    265CC9D44EA4F57D
MGEEVVQALVVDNGSGNVKAGVAGDDAPRSVFPSIVGRPKNPGIMVGMEEKDAFVGDEAQTKRGILTLKYPIEHGIVTNWDDMEKIWHHTFYNELRAAPEEHPVLLTEAPLNPKGNRERMTQIMFESFNVPAMYVAIQAVLSLYSSGRTTGIVLDSGDGVSHTVPIYEGYALPHAIMRLDLAGRDLTEYLMKILHERGYGFSTSAEKEIVRDIKEKLCYIALNFDEEMKTSEQSSDIEKSYELPDGNIITVGNERFRCPEALFQPSFLGKEAAGIHTTTFNSIKKCDVDIRKDLYGNIVLSGGTTMYEGTGERLTRDITTLAPSTMKIKVVAPPERKYSVWIGGSILSSLSTFQQMWITKEEYDESGPSIVHRKCF

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
M19146
EMBL· GenBank· DDBJ
AAA29464.1
EMBL· GenBank· DDBJ
mRNA
M22719
EMBL· GenBank· DDBJ
AAA29465.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

Disclaimer

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