Peptidyl-prolyl cis-trans isomerase PIN1 binds to PIP4K2B phosphorylated at serine residue S326. PIP4K2B is phosphorylated at S326 under conditions of cellular stress, such as increased level of reactive oxygen species (ROS). Phosphorylation of PIP4K2B at threonine residue T322 may also contribute to PIN1 binding. PIN1 induces conformational change of PIP4K2B, resulting in inactivation of PIP4K2B dimers. This enables increase of the nuclear PI5P levels. PI5P positively regulates expression of genes involved in neutralization of ROS (Keune et al. 2012).