TPX2 is a key component in the formation of the mitotic spindle

Mitotic spindle with TPX2 expression (green)

TPX2 was identified in 1997 as a 100 kDa nuclear protein. In cells TPX2, a is a microtubule nucleation factor that translocates from the nucleus - where it resides during interphase - to the mitotic spindle during mitosis.

The mitotic spindle forms when chromosomes are ready to segregate during cell division and not surprisingly this protein is also found in this specific compartment of the cell! TPX2 is required for the correct formation of the kinetochores that is crucial for the attachment of microtubules, enabling the sister chromatids to be pulled apart. Due to its function TPX2 expression is cell-cycle dependent.

TPX2 is a clinically relevant protein due to aberrant expression patterns found among various tumor types, especially in colon cancer where it has been shown to be overexpressed in metastatic lesions and therefore considered a prognostic marker for the gain of metastatic capabilities. Due to its role in formation of tumors and metastases, TPX2 is also a potential therapeutic target for the disease.