PMID- 10523642 OWN - NLM STAT- MEDLINE DCOM- 19991124 LR - 20190508 IS - 0270-7306 (Print) IS - 0270-7306 (Linking) VI - 19 IP - 11 DP - 1999 Nov TI - JSAP1, a novel jun N-terminal protein kinase (JNK)-binding protein that functions as a Scaffold factor in the JNK signaling pathway. PG - 7539-48 AB - The major components of the mitogen-activated protein kinase (MAPK) cascades are MAPK, MAPK kinase (MAPKK), and MAPKK kinase (MAPKKK). Recent rapid progress in identifying members of MAPK cascades suggests that a number of such signaling pathways exist in cells. To date, however, how the specificity and efficiency of the MAPK cascades is maintained is poorly understood. Here, we have identified a novel mouse protein, termed Jun N-terminal protein kinase (JNK)/stress-activated protein kinase-associated protein 1 (JSAP1), by a yeast two-hybrid screen, using JNK3 MAPK as the bait. Of the mammalian MAPKs tested (JNK1, JNK2, JNK3, ERK2, and p38alpha), JSAP1 preferentially coprecipitated with the JNKs in cotransfected COS-7 cells. JNK3 showed a higher binding affinity for JSAP1, compared with JNK1 and JNK2. In similar cotransfection studies, JSAP1 also interacted with SEK1 MAPKK and MEKK1 MAPKKK, which are involved in the JNK cascades. The regions of JSAP1 that bound JNK, SEK1, and MEKK1 were distinct from one another. JNK and MEKK1 also bound JSAP1 in vitro, suggesting that these interactions are direct. In contrast, only the activated form of SEK1 associated with JSAP1 in cotransfected COS-7 cells. The unstimulated SEK1 bound to MEKK1; thus, SEK1 might indirectly associate with JSAP1 through MEKK1. Although JSAP1 coprecipitated with MEK1 MAPKK and Raf-1 MAPKKK, and not MKK6 or MKK7 MAPKK, in cotransfected COS-7 cells, MEK1 and Raf-1 do not interfere with the binding of SEK1 and MEKK1 to JSAP1, respectively. Overexpression of full-length JSAP1 in COS-7 cells led to a considerable enhancement of JNK3 activation, and modest enhancement of JNK1 and JNK2 activation, by the MEKK1-SEK1 pathway. Deletion of the JNK- or MEKK1-binding regions resulted in a significant reduction in the enhancement of the JNK3 activation in COS-7 cells. These results suggest that JSAP1 functions as a scaffold protein in the JNK3 cascade. We also discuss a scaffolding role for JSAP1 in the JNK1 and JNK2 cascades. FAU - Ito, M AU - Ito M AD - Department of Biosciences, School of Science, Kitasato University, Kanagawa 228, Japan. FAU - Yoshioka, K AU - Yoshioka K FAU - Akechi, M AU - Akechi M FAU - Yamashita, S AU - Yamashita S FAU - Takamatsu, N AU - Takamatsu N FAU - Sugiyama, K AU - Sugiyama K FAU - Hibi, M AU - Hibi M FAU - Nakabeppu, Y AU - Nakabeppu Y FAU - Shiba, T AU - Shiba T FAU - Yamamoto, K I AU - Yamamoto KI LA - eng SI - GENBANK/AB005662 SI - GENBANK/AB005663 SI - GENBANK/AB005664 SI - GENBANK/AB005665 SI - GENBANK/AB014614 PT - Comparative Study PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - United States TA - Mol Cell Biol JT - Molecular and cellular biology JID - 8109087 RN - 0 (Adaptor Proteins, Signal Transducing) RN - 0 (Carrier Proteins) RN - 0 (Mapk8ip3 protein, mouse) RN - 0 (Nerve Tissue Proteins) RN - EC 2.7.- (Protein Kinases) RN - EC 2.7.1.- (Mitogen-Activated Protein Kinase 10) RN - EC 2.7.1.24 (Mitogen-Activated Protein Kinase 9) RN - EC 2.7.10.1 (Protein-Tyrosine Kinases) RN - EC 2.7.11.1 (Protein-Serine-Threonine Kinases) RN - EC 2.7.11.24 (JNK Mitogen-Activated Protein Kinases) RN - EC 2.7.11.24 (Mitogen-Activated Protein Kinases) RN - EC 2.7.11.25 (MAP Kinase Kinase Kinase 1) RN - EC 2.7.11.25 (MAP Kinase Kinase Kinases) RN - EC 2.7.11.25 (Map3k1 protein, mouse) RN - EC 2.7.12.2 (MAP Kinase Kinase 4) RN - EC 2.7.12.2 (Map2k4 protein, mouse) RN - EC 2.7.12.2 (Mitogen-Activated Protein Kinase Kinases) SB - IM MH - *Adaptor Proteins, Signal Transducing MH - Amino Acid Sequence MH - Animals MH - Carrier Proteins/genetics/*metabolism MH - Cloning, Molecular MH - Enzyme Activation MH - JNK Mitogen-Activated Protein Kinases MH - *MAP Kinase Kinase 4 MH - *MAP Kinase Kinase Kinase 1 MH - MAP Kinase Kinase Kinases/metabolism MH - *MAP Kinase Signaling System MH - Mice MH - Mitogen-Activated Protein Kinase 10 MH - Mitogen-Activated Protein Kinase 9 MH - Mitogen-Activated Protein Kinase Kinases/metabolism MH - Mitogen-Activated Protein Kinases/*metabolism MH - Molecular Sequence Data MH - *Nerve Tissue Proteins MH - Phosphorylation MH - Protein Binding MH - Protein Kinases/metabolism MH - *Protein-Serine-Threonine Kinases MH - Protein-Tyrosine Kinases/*metabolism MH - Two-Hybrid System Techniques PMC - PMC84763 EDAT- 1999/10/19 00:00 MHDA- 1999/10/19 00:01 CRDT- 1999/10/19 00:00 PHST- 1999/10/19 00:00 [pubmed] PHST- 1999/10/19 00:01 [medline] PHST- 1999/10/19 00:00 [entrez] AID - 10.1128/mcb.19.11.7539 [doi] PST - ppublish SO - Mol Cell Biol. 1999 Nov;19(11):7539-48. doi: 10.1128/mcb.19.11.7539.