Figure 1.

Classical and non-classical functions of CHKA. The classical model involves ubiquitination and activation of AR-dependent transcription that results in upregulation of CHKA, a rate-limiting enzyme in the Kennedy pathway (production of phosphatidylcholine, required for plasma membrane biogenesis). In addition to its role in the Kennedy pathway, CHKA can also interact with the AR in the cytoplasm and promote its stability (non-classical model). This could lead to AR overexpression and increased AR signaling, which in turn may allow more CHKA production. AR,  androgen receptor; CHKA, choline kinase α; U, ubiquitin.