SPIRE1
Description
The SPIRE1 (spire type actin nucleation factor 1) is a protein-coding gene located on chromosome 18.
SPIRE1 is a protein that interacts with actin monomers and actin nucleating formin proteins. SPIRE1 was first identified in Drosophila melanogaster. SPIRE1 contains an N-terminal KIND domain which binds formins and four actin-binding WH2 domains which nucleate actin filaments.
SPIRE1 acts as an actin nucleation factor, remaining associated with the pointed end of newly formed actin filaments. It participates in intracellular vesicle transport along actin fibers, linking actin cytoskeleton dynamics to intracellular transport. SPIRE1 is essential for asymmetric spindle positioning and asymmetric cell division during meiosis, and it plays a crucial role in the formation of the cleavage furrow and polar body extrusion during female germ cell meiosis. Additionally, SPIRE1 functions within the nucleus, promoting the assembly of nuclear actin filaments in response to DNA damage to facilitate chromatin movement and repair factor recruitment. Furthermore, SPIRE1 promotes innate immune signaling downstream of dsRNA sensing by contributing to IRF3 phosphorylation and activation downstream of MAVS and upstream of TBK1.
SPIRE1 is also known as Spir-1.
