SPIRE1
Domain
Binds to actin monomers via the WH2 domain.
The Spir-box targets binding to intracellular membrane structures.
Function
Acts as an actin nucleation factor, remains associated with the slow-growing pointed end of the new filament (PubMed:11747823, PubMed:21620703). Involved in intracellular vesicle transport along actin fibers, providing a novel link between actin cytoskeleton dynamics and intracellular transport (PubMed:11747823). Required for asymmetric spindle positioning and asymmetric cell division during meiosis (PubMed:21620703). Required for normal formation of the cleavage furrow and for polar body extrusion during female germ cell meiosis (PubMed:21620703). Also acts in the nucleus: together with FMN2, promotes assembly of nuclear actin filaments in response to DNA damage in order to facilitate movement of chromatin and repair factors after DNA damage (PubMed:26287480). In addition, promotes innate immune signaling downstream of dsRNA sensing (PubMed:35148361). Mechanistically, contributes to IRF3 phosphorylation and activation downstream of MAVS and upstream of TBK1 (PubMed:35148361).
Sequence Similarities
Belongs to the spire family.
Cellular localization
- Cytoplasm
- Cytoskeleton
- Cytoplasm
- Perinuclear region
- Cell membrane
- Peripheral membrane protein
- Cytoplasmic side
- Cytoplasmic vesicle membrane
- Peripheral membrane protein
- Cytoplasmic side
- Detected at the cleavage furrow during asymmetric oocyte division and polar body extrusion (By similarity). Punctate spots in perinuclear region and cytoplasm, colocalized with Rab11 (By similarity).
Alternative names
KIAA1135, SPIR1, SPIRE1, Protein spire homolog 1, Spir-1