Component of the ska-1 complex, a microtubule-binding subcomplex of the outer kinetochore that is essential for proper chromosome segregation (PubMed:23085020). Required for timely anaphase onset during mitosis, when chromosomes undergo bipolar attachment on spindle microtubules leading to silencing of the spindle checkpoint (By similarity). The ska-1 complex is a direct component of the kinetochore-microtubule interface and directly associates with microtubules as oligomeric assemblies (By similarity). The complex facilitates the processive movement of microspheres along a microtubule in a depolymerization-coupled manner (By similarity). Affinity for microtubules is synergistically enhanced in the presence of the ndc-80 complex and may allow the ndc-80 complex to track depolymerizing microtubules (PubMed:23085020). In the complex, it mediates the interaction with microtubules (PubMed:23085020). Component of the ska-1 complex, composed of two copies of ska-1 and a single copy of ska-3. The core complex associates with microtubules and may form dimeric assemblies. Interacts with ska-3 and microtubules. Belongs to the SKA1 family.