Contributes to the assembly of the acentrosomal spindle and phragmoplast microtubule arrays as part of the augmin complex. Part of the augmin complex composed of 8 subunits. The complex acts on microtubules and interacts with gamma-tubulin in spindles and the phragmoplast. Preferentially localizes to microtubules minus ends. Belongs to the HAUS6 family.