Distinct Domains of Mouse Dishevelled Are Responsible for the c-Jun N-terminal Kinase/Stress-activated Protein Kinase Activation and the Axis Formation in Vertebrates

Abstract

Recent studies have shown that Drosophila Dishevelled (Dsh), an essential component of the wingless signal transduction, is also involved in planar polarity signaling through the c-Jun N-terminal kinase (JNK)/ stress-activated protein kinase (SAPK) pathway in Drosophila. Here, we show that expression of a mouse homolog of Dsh (mDvl-1) in NIH3T3 cells activates JNK/ SAPK, and its activator MKK7. A C-terminal half of mDvl-1 which contains the DEP domain was sufficient for the activation of JNK/SAPK, whereas an N-terminal half of mDvl-1 as well as the DEP domain is required for stimulation of the TCF/LEF-1-dependent transcriptional activation, a ␤-catenin-dependent process. A single amino acid substitution (Met for Lys) within the DEP domain (mDvl-1 (KM)) abolished the JNK/SAPK-activating activity of mDvl-1, but did not affect the activity to activate the LEF-1-dependent transcription. Ectopic expression of mDvl-1 (KM) or an N-terminal half of mDvl-1, but not the C-terminal, was able to induce secondary axis in Xenopus embryos. Because the secondary axis formation is dependent on the Wnt/␤-catenin signaling pathway, these results suggest that distinct domains of mDvl-1 are responsible for the two downstream signaling pathways, the ␤-catenin pathway and the JNK/SAPK pathway in vertebrates. c-Jun N-terminal kinase (JNK)1 /stress-activated protein kinase (SAPK), a member of mitogen-activated protein kinases (MAPKs) (1-4), is activated by exposure of cells to certain kinds of cytokines and environmental stresses (4 -7). Two MAPK kinases (MAPKKs), MKK4/SEK1 and MKK7, act as direct activators for JNK/SAPK (4 -12). Although several members of MAPKK kinases, Ste20 homologs, protein-tyrosine kinases, and low molecular weight GTPases have been described as upstream components of the JNK/SAPK signaling pathway, players involved in signaling pathways have not been completely listed up, and exact signaling pathways from receptors or sensors to the activation of JNK/SAPK have not been fully understood.The Wnt proteins constitute a family of secreted glycoproteins, among which Wingless (Wg) in Drosophila is the best characterized member. Genetic evidence reveals that Wg signals through an intracellular cascade that includes Dishevelled (Dsh), Zeste-White3/Shaggy and Armadillo, a ␤-catenin homolog (13). There exist vertebrate counterparts of these genes, and the corresponding cascade is believed to function in a variety of biological processes (14, 15). Of the known components, Dsh is thought to act most immediately downstream of the receptor. Alignment of members of invertebrate and vertebrate Dsh family proteins (16 -19) reveals three conserved domains: a DIX domain, a PDZ domain, and a DEP domain (20). Recent analysis of the planar polarity-specific dsh 1 allele in Drosophila revealed a single amino acid point mutation in the DEP domain and demonstrated requirement of the DEP domain for planar polarity signaling but not for wingless signaling (21, 22). Moreover, it has been shown that Dsh may act through low molecular weight GT...

JNK and ROKα function in the noncanonical Wnt/RhoA signaling pathway to regulate Xenopus convergent extension movements

“…Whereas Dsh regulates JNK activation through its DEP domain (Boutros et al, 1998;Li et al, 1999;Moriguchi et al, 1999;Habas et al, 2003), the involvement of Rho GTPases in JNK activation by Dsh remains unclear in mammalian cells (Li et al, 1999;Moriguchi et al, 1999;Habas et al, 2003). Moreover, the precise molecular mechanism by which Rho GTPases regulate JNK activation in Wnt/PCP pathway during Xenopus CE movements has been unknown.…”

“…Cdc42 regulates Xenopus CE movements through the Wnt/Ca 2ϩ pathway (Djiane et al, 2000;Choi and Han, 2002;Penzo-Mendez et al, 2003), and mediates JNK activation by Dsh in mammalian cell (Moriguchi et al, 1999). We have examined whether Cdc42 is required for JNK activation by Dsh in Keller explants.…”

Controlled levels of canonical Wnt signaling are required for neural crest migration

“…DIX (Disheveled/Axin) domain located at the N-terminus (Capelluto et al, 2002) is responsible for interaction with a scaffolding protein Axin and functions exclusively in canonical Wnt signaling (Axelrod et al, 1998;Boutros et al, 1998; A B Moriguchi et al, 1999;Penton et al, 2002;Rothbächer et al, 2000). PZD (PSD-95, DLG, ZO1) domain located in the center mediates protein-protein interactions (Cheyette et al, 2002;Wong et al, 2003) and is required for all branches of Wnt signaling (Axelrod et al, 1998;Boutros et al, 1998;Moriguchi et al, 1999;Penton et al, 2002;Rothbächer et al, 2000). Finally, the DEP (Disheveled, EGL-10, Pleckstrin) domian situated at the C-terminus is essential for PCP signaling (Heisenberg et al, 2000;Moriguchi et al, 1999;Tada and Smith, 2000;Wallingford et al, 2000).…”

“…PZD (PSD-95, DLG, ZO1) domain located in the center mediates protein-protein interactions (Cheyette et al, 2002;Wong et al, 2003) and is required for all branches of Wnt signaling (Axelrod et al, 1998;Boutros et al, 1998;Moriguchi et al, 1999;Penton et al, 2002;Rothbächer et al, 2000). Finally, the DEP (Disheveled, EGL-10, Pleckstrin) domian situated at the C-terminus is essential for PCP signaling (Heisenberg et al, 2000;Moriguchi et al, 1999;Tada and Smith, 2000;Wallingford et al, 2000).…”

“…Dsh to the cell membrane, but on the contrary to the canonical Wnt pathway, interactions with downstream targets is performed by the PDZ and DEP domains (Cheyette et al, 2002;Wong et al, 2003;Heisenberg et al, 2000;Moriguchi et al, 1999;Tada and Smith, 2000;Wallingford et al, 2000). Once Dsh is properly localized it affects cytoskeleton rearrangement via two distinct small GTPases-dependent pathways, namely Rho-and Rac-pathways.…”