ACTL10

Model summary

A cytoplasmic actin-fold protein that uses an ATPase-like nucleotide-binding core to regulate cytoskeletal dynamics. By engaging actin and actin-binding proteins through multivalent interfaces, it biases filament turnover toward depolymerization and recycling. Its soluble architecture situates it within cytoskeletal assemblies and also enables incorporation into extracellular vesicles, linking cytoskeletal remodeling to vesicular pathways.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture.

   The sequence is dominated by IPR004000 (Actin family, residues 1–244), which defines a canonical actin fold composed of two lobes that cradle a nucleotide and undergo Mg2+-dependent conformational switching. Nested within this, IPR043129 (ATPase, nucleotide binding domain homologous superfamily, residues 13–242) marks the conserved P-loop–like nucleotide-binding core that coordinates ATP/ADP and couples hydrolysis to structural rearrangements. The order—an N-terminal-to-C-terminal actin family scaffold fully encompassing a central ATPase/nucleotide-binding core—establishes a mechano-chemical module: ATP binding and hydrolysis drive transitions between monomeric and filament-associated states.

2. 02

   This actin-fold architecture causes a molecular function centered on multivalent protein binding (GO:0005515).

   The actin fold exposes hydrophobic surfaces and subdomain interfaces that mediate high-affinity contacts with actin-binding proteins and with actin itself. Although the fold is ATPase-competent, in this paralog the kinetics and surface chemistry bias the system toward binding and regulation rather than robust filament assembly. The ATPase core stabilizes distinct conformations that tune affinity for partners and for filament ends.

3. 03

   From this molecular function, the biological process follows: actin filament dynamics are governed by cycles of polymerization and depolymerization.

   The actin fold and its ATPase-driven conformational states enable controlled disassembly, aligning with actin filament depolymerization (GO:0030042). By sequestering monomers and modulating end-associated factors, this protein can bias the system toward turnover and clearance of filament ends, thereby shaping filament lifetimes and spatial organization.

4. 04

   Cellular localization is inferred from the soluble actin-fold and absence of transmembrane features, placing the protein in the cytoplasm and associating it with cytoskeletal assemblies.

   This matches a cytoplasmic, cytoskeleton-associated residency and explains its role in filament turnover. Additionally, actin-family proteins are frequently trafficked in extracellular vesicles; the presence in extracellular exosome (GO:0070062) is consistent with cytoskeletal cargo being packaged into vesicles and secreted.

5. 05

   Mechanistically, I hypothesize that the actin fold here operates as a regulatory actin-like module that binds actin and actin-binding proteins to modulate filament turnover.

   It likely associates with monomer pools and end-capping or severing factors to accelerate depolymerization in specific cellular territories. Packaging into exosomes suggests transient interactions with vesicle biogenesis machinery, potentially coupling cytoskeletal remodeling to vesicular export pathways.

6. 06

   From these features, I predict interaction with core actin regulators: monomer carriers and filament-end modulators that together drive depolymerization and recycling.

   Likely partners include profilin and cofilin for monomer flux and filament severing, ADF/cofilin complexes, Arp2/3-associated factors for branch turnover, and exosome biogenesis adaptors that transiently bind cytoskeletal cargo during vesicle formation.