P10988 · ACT1_PLAFO
- ProteinActin-1
- GeneACT1
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids376 (go to sequence)
- Protein existenceEvidence at transcript level
- Annotation score3/5
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
- ATP + H2O = ADP + H+ + phosphate
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.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 15 | ATP (UniProtKB | ChEBI) | ||||
Sequence: S | ||||||
Binding site | 16 | ATP (UniProtKB | ChEBI) | ||||
Sequence: G | ||||||
Binding site | 17 | ATP (UniProtKB | ChEBI) | ||||
Sequence: N | ||||||
Binding site | 19 | ATP (UniProtKB | ChEBI) | ||||
Sequence: K | ||||||
Binding site | 158 | ATP (UniProtKB | ChEBI) | ||||
Sequence: D | ||||||
Binding site | 159 | ATP (UniProtKB | ChEBI) | ||||
Sequence: G | ||||||
Binding site | 160 | ATP (UniProtKB | ChEBI) | ||||
Sequence: V | ||||||
Binding site | 214 | ATP (UniProtKB | ChEBI) | ||||
Sequence: K | ||||||
Binding site | 215 | ATP (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Binding site | 303 | ATP (UniProtKB | ChEBI) | ||||
Sequence: G |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | actin filament | |
Cellular Component | cytoplasm | |
Cellular Component | nucleus | |
Molecular Function | ATP binding | |
Molecular Function | hydrolase activity | |
Molecular Function | structural constituent of cytoskeleton | |
Biological Process | symbiont-medited actin polymerization-dependent cell-to-cell migration in host |
Keywords
- Molecular function
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameActin-1
- EC number
- Alternative names
Gene names
Organism names
- Taxonomic lineageEukaryota > Sar > Alveolata > Apicomplexa > Aconoidasida > Haemosporida > Plasmodiidae > Plasmodium > Plasmodium (Laverania)
Accessions
- Primary accessionP10988
Subcellular Location
UniProt Annotation
GO Annotation
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).
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
- Cellular component
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000088994 | 1-376 | Actin-1 | |||
Sequence: MGEEVVQALVVDNGSGNVKAGVAGDDAPRSVFPSIVGRPKNPGIMVGMEEKDAFVGDEAQTKRGILTLKYPIEHGIVTNWDDMEKIWHHTFYNELRAAPEEHPVLLTEAPLNPKGNRERMTQIMFESFNVPAMYVAIQAVLSLYSSGRTTGIVLDSGDGVSHTVPIYEGYALPHAIMRLDLAGRDLTEYLMKILHERGYGFSTSAEKEIVRDIKEKLCYIALNFDEEMKTSEQSSDIEKSYELPDGNIITVGNERFRCPEALFQPSFLGKEAAGIHTTTFNSIKKCDVDIRKDLYGNIVLSGGTTMYEGTGERLTRDITTLAPSTMKIKVVAPPERKYSVWIGGSILSSLSTFQQMWITKEEYDESGPSIVHRKCF |
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).
Interacts with DNase I with low affinity (By similarity).
Structure
Family & Domains
Features
Showing features for region.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Region | 40-61 | DNAseI-binding D loop; regulates polymerization and stability of the actin filament | ||||
Sequence: KNPGIMVGMEEKDAFVGDEAQT |
Sequence similarities
Belongs to the actin family.
Family and domain databases
Sequence
- Sequence statusComplete
- Length376
- Mass (Da)41,843
- Last updated1989-07-01 v1
- Checksum265CC9D44EA4F57D