Hyperphosphorylation of JNK-interacting protein 1, a protein associated with Alzheimer disease.
The c-Jun N-terminal kinase (JNK) group of mitogen-activated 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 establishes an interaction with beta-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 activation of stress-activated and MAP kinases. By immobilized metal affinity chromatography and a combined microcapillary 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/Thr)-Pro sequence. This motif is modified by various kinases in aggregates of the microtubule-associated protein tau, which generates typical intraneuronal lesions occurring in Alzheimer disease. Most of the post-translational modifications found were located within the JNK, MAP kinase kinase, and RAC-alpha Ser/Thr protein kinase binding regions; no modifications occurred in protein Src homology 3 and phosphotyrosine interaction domains, which are essential for binding to kinesin, beta-amyloid precursor protein, and MAP kinase kinase kinase. Protein phosphorylation is known to affect stability and protein-protein interactions. Thus, the findings that JIP1 is extensively phosphorylated after activation of stress-activated and MAP kinases indicate that these signaling pathways might modulate JIP1 signaling by regulating its stability and association with some, but not all, interacting proteins.
D'Ambrosio
Chiara
C
Proteomics and Mass Spectrometry Laboratory, ISPAAM, National Research Council, 80147 Naples, Italy.
Arena
Simona
S
Fulcoli
Gabriella
G
Scheinfeld
Meir H
MH
Zhou
Dawang
D
D'Adamio
Luciano
L
Scaloni
Andrea
A
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000544:Alzheimer Disease / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000378:metabolism; D000841:Anisomycin / Q000494:pharmacology; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D006801:Humans; D047468:Immunoprecipitation; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D010766:Phosphorylation; D011485:Protein Binding; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013912:Threonine / Q000737:chemistry
D048868:Adaptor Proteins, Signal Transducing; D016229:Amyloid beta-Peptides; C490666:MAPK8IP1 protein, human; D010446:Peptide Fragments; D013912:Threonine; D012694:Serine; D000841:Anisomycin; D051057:Proto-Oncogene Proteins c-akt; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases