Speckle-type POZ adaptor protein (SPOP) and its role in cancer

Proteasomal degradation is an essential regulatory mechanism for cellular homeostasis maintenance. The speckle-type POZ adaptor protein (SPOP) is part of the ubiquitin ligase E3 cullin-3 RING-box1 complex, responsible for the ubiquitination and proteasomal degradation of biomolecules involved in cell cycle control, proliferation, response to DNA damage, epigenetic control, and hormone signaling, among others. Changes in SPOP have been associated with the development of different types of cancer, since it can act as a tumor suppressor mainly in prostate, breast, colorectal, lung cancer and liver cancer, due to point mutations and/or reduced expression, or as an oncogene in endometrial cancer, in which function gain has been found, and in kidney cancer by protein overexpression. SPOP is a potential prognostic biomarker and a promising therapeutic target.