Hyperphosphorylation of JNK-interacting protein 1, a protein associated with Alzheimer disease. Mol. Cell Proteomics 5:97–113

The c-Jun N-terminal kinase (JNK) group of mitogen-acti-vated protein (MAP) kinases are activated by pleiotropic signals including environmental stresses, growth factors, and hormones. JNK-interacting protein 1 (JIP1) is a scaffold protein that assembles and facilitates the activation of the mixed lineage kinase-dependent JNK module and also es-tablishes an interaction with -amyloid precursor protein that has been partially characterized. Here we show that, similarly to other proteins involved in various neurological diseases, JIP1 becomes hyperphosphorylated following ac-tivation of stress-activated and MAP kinases. By immobi-lized metal affinity chromatography and a combined micro-capillary LC/MALDI-TOF/ESI-ion trap mass spectrometry approach, we identified 35 sites of mitotic phosphorylation within JIP1, among which eight were present within (Ser