Essential component of the mitotic spindle required for faithful chromosome segregation and progression into anaphase . Promotes the metaphase-to-anaphase transition and is required for chromosome alignment, normal timing of sister chromatid segregation, and maintenance of spindle pole architecture (, ). The astrin (SPAG5)-kinastrin (SKAP) complex promotes stable microtubule-kinetochore attachments . Required for kinetochore oscillations and dynamics of microtubule plus-ends during live cell mitosis, possibly by forming a link between spindle microtubule plus-ends and mitotic chromosomes to achieve faithful cell division . May be involved in UV-induced apoptosis via its interaction with PRPF19; however, these results need additional evidences .
Subcellular locations: Nucleus, Chromosome, Centromere, Kinetochore, Cytoplasm, Cytoskeleton, Spindle pole, Cytoplasm, Cytoskeleton, Microtubule organizing center
Colocalizes with microtubules around centrosomes in prophase and with the mitotic spindle at prometaphase and metaphase. From late prometaphase to anaphase, is highly concentrated on kinetochores. Located at the kinetochore-microtubule interface. The astrin (SPAG5)-kinastrin (SKAP) complex localizes to the microtubule plus ends .
Widely expressed, including in skin.