Abstract: The expression of brain aquaporin 4 (AQP4) is different at the different stages of cellular differentiation, and distribution of brain AQP4 is affected by the existence of endothelial cells. Other factors including osmolality, ammonia, hypoxia, temperature, hormone, C-type natriuretic peptide, lead, complement inhibitor, lipopolysaccharide can also influence AQP4 expression in astrocytes. However, the regulating mechanisms for brain AQP4 expression are not clear. Protein interaction, protein kinase C (PKC) through protein phosphorylation, mitogen-activated protein kinase signal pathway, Ca²⁺ signaling cascade signal pathway and transcription factor pathway have been proposed, among which phosphorylation of PKC for the inhibition of AQP4 is frequently studied.

Key words: aquaporin 4, protein kinase C, phosphorylation, mitogen-activated protein kinase, review