Protein family; a representative (GI) | Detection in proteomic studies (number of species, out of 5 studied) | Role in phagocytosis | Domain architecture (with CDD IDs)band structural features (N-C)c | Range of orthologs in eukaryotes | Prokaryotic homologs | References |
---|---|---|---|---|---|---|
Actin 66826069 | 4 (except for Tetrahymena) | Actin filament rearrangement is the universal mechanical basis for phagosome formation | Actin (cd00012) | All eukaryotes | A group of Crenarchaeal-Korarchaeal proteins are the closest prokaryotic orthologs of actins; MreB, FtsA, ParM, MamK and their euryarchaeal homologs (Ta0583) are distant prokaryotic homologs (see main text for details). | [113] |
Actin-related protein 2/3 (ARP2/3) complex – 7 subunits | ||||||
Actin-related protein 2 (ARP2) 4093161 | 1(Entamoeba) | Enables branching of actin filaments by providing new nucleation sites for G-actin. Arp2/3 complex is essential for apparently all known types of phagocytosis (not documented in Ciliata) | Actin (cd00012) | All eukaryotes except for Diplomonadida | Same as for actins | |
Actin-related protein 3 (ARP3) 60467470 | 3 (except for Tetrahymena and Entamoeba) | Â | Actin (cd00012) | All eukaryotes except for Diplomonadida | Â | Â |
ARP complex(ARPC) protein 1 (p41-Arc) 66816255 | 2 (Drosophila and Entamoeba) | Â | WD40 domain (cl02567) | All eukaryotes except for Diplomonadida and Chlorophyta | No orthologs but proteins containing WD40 domains are common in bacteria, particularly, those with complex signal transduction systems. | Â |
ARPC2 (p34-Arc) 60467975 | 0 | Â | p34-Arc (pfam04045) | All eukaryotes except for Diplomonadida and Apicomplexa | none | Â |
ARPC3 (p21-Arc) 50344884 | 1(Entamoeba) | Â | p21-Arc (pfam04062) | All eukaryotes except for Diplomonadida and Apicomplexa | none | Â |
ARPC4 (p20-Arc) 115495705 | 2 (mouse and Entamoeba) | Â | ARPC4 (pfam05856) | All eukaryotes except for Diplomonadida | None | Â |
ARPC5 (p16-Arc) 66806101 | 0 | Â | p16-Arc (pfam04699) | absent in Diplomonadida, Apicomplexa, Chlorophyta, Choanoflagellida, and Ciliophora | None | Â |
WASp (Wiskott-Aldrich syndrome protein) 10880935 | 0 Entamoeba proteome contained RickA protein, acting as WASp (167383163) | Actin assembly factor, activates the Arp2/3 complex | WH1-irregular superhelix (proline-rich; cd01205) WH1 is a derived plekstrin homology (PH) domain Cdc42/Rac interactive binding (CRIB) motif (cd00132) | All animals and fungi, Monosiga, Dictyostelium, Entamoeba, ciliates, Trichomonas; missing in plants | None PH-fold is, largely, specific to eukaryotes. Some pathogenic bacteria have proteins that mimics WASp: RickA (168824102, Rickettsia raoultii), ActA (58500210, Listeria seeligeri). | |
WAVE1/SCAR1 66809177 | 1 (Drosophila) | Actin assembly factor, activates the Arp2/3 complex | WH1-unstructured (proline-rich) Paralog of WASp, diverged variant of WH1 domain | All animals and plants, Dictyostelium, Monosiga, Trichomonas | None | |
Profilin 730406 | 3 (except for Tetrahymena and Dictyostelium) | Regulator of actin polymerization, stoichiometric complex with actin, activator of WASP and SCAR (binds to their prolin-rich regions), lipid-binding | Profilin domain (cd00148) | All eukaryotes with the apparent exception of Diplomonadida | No orthologs. Profilin-like fold found in PAS and GAF signaling domains that are common in bacteria, and Roadblock/LC7 domain that is present in bacteria and some archaea, and interacts with small GTPases | |
Formin 158518557 | 3 (except for Tetrahymena and Dictyostelium) | nucleates the formation of linear actin filaments | Globular -unstructured proline-rich -FH2 (formin homology) | Multiple paralogs, apparently, in all eukaryotes except for Diplomonadida | None FH2 is a unique fold restricted to eukaryotes | |
Cofilin/ADF 3182971 | 4 (except for Tetrahymena) | reversibly controls actin polymerization and depolymerization | Cofilin domain cd00013, ADF, Actin depolymerisation factor/cofilin -like domains | Multiple paralogs, apparently, in all eukaryotes except for Diplomonadida | A homolog only in Streptomyces (112791749), probable HGT | [80] |
Coronin 11023 | 2 (mouse and Dictyostelium) | associates with the Arp2p/Arp3p complex to regulate its activity | WD40 (cl02567) | Apparently, single orthologs in all eukaryotes except for Diplomonadida, green algae, plants | No orthologs but numerous WD40-domain proteins are present, primarily, in bacteria with complex signal transduction systems | |
alpha-actinin 60474969 | 3 (except for Tetrahymena and Dictyostelium). An actin cross-linker cortexillin (ctxA, 66804885) is found on Dictyostelium phagosome. | cross-links actin filaments; involved in membrane anchoring actin filaments. | CH-SPEC-EF-hands (actin-binding domain composed of two calponin homology (CH) domains (cd00014); spectrin repeats (SPEC, cd00176); EF-hand, calcium-binding domain (cd00051) | Animals, fungi, amoebozoa, Monosiga, Trichomonas, oomycetes; in plants, green alga, Ciliata, Apicomplexa, Kinetoplastida, Diplomonada have other EF-hand family proteins | No orthologs or homologs with high similarity but many bacteria encode EF-hand-containing proteins (e.g., 148256632) | |
Filamin/ABP120 121115 | 3 (except for Tetrahymena and Dictyostelium). An actin cross-linker cortexillin (ctxA, 66804885) is found on Dictyostelium phagosome. | Cross-links actin filaments | Actin-binding domain composed of two CH domains (cd00014); Filamin/ABP280 repeats (cl02665) | Animals and amoebozoa; others eukaryotes have non-orthologous EF-hand family proteins; plants have multiple CH domain proteins | None |