Involved in microtubules reorganization during spindle and phragmoplast development. 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. Lethal when homozygous. Belongs to the HAUS5 family. Truncated N-terminus.