Spindle assembly factor required for normal assembly of mitotic spindles. Required for normal assembly of microtubules during apoptosis. Required for chromatin and/or kinetochore dependent microtubule nucleation. Mediates AURKA localization to spindle microtubules. Activates AURKA by promoting its autophosphorylation at 'Thr-288' and protects this residue against dephosphorylation. TPX2 is inactivated upon binding to importin-alpha. At the onset of mitosis, GOLGA2 interacts with importin-alpha, liberating TPX2 from importin-alpha, allowing TPX2 to activates AURKA kinase and stimulates local microtubule nucleation. Interacts with AURKA (PubMed:18663142). Interacts with importin-alpha; leading to inactivate TPX2 (By similarity). Interacts with HNRNPU; this interaction recruits HNRNPU to spindle microtubules (MTs) (By similarity). Interacts with BCL2L10 (PubMed:27753540). During mitosis it is strictly associated with the spindle pole and with the mitotic spindle, whereas during S and G2, it is diffusely distributed throughout the nucleus. Is released from the nucleus in apoptotic cells and is detected on apoptotic microtubules. Expressed during all phases of oocyte maturation; localized at the meiotic spindle and microtubule organizing center during meiosis. Belongs to the TPX2 family.