The C. elegans Discoidin Domain Receptor DDR-2 Modulates the Met-like RTK–JNK Signaling Pathway in Axon Regeneration

Abstract

The ability of specific neurons to regenerate their axons after injury is governed by cell-intrinsic regeneration pathways. However, the signaling pathways that orchestrate axon regeneration are not well understood. In Caenorhabditis elegans, initiation of axon regeneration is positively regulated by SVH-2 Met-like growth factor receptor tyrosine kinase (RTK) signaling through the JNK MAPK pathway. Here we show that SVH-4/DDR-2, an RTK containing a discoidin domain that is activated by collagen, and EMB-9 collagen type IV regulate the regeneration of neurons following axon injury. The scaffold protein SHC-1 interacts with both DDR-2 and SVH-2. Furthermore, we demonstrate that overexpression of svh-2 and shc-1 suppresses the delay in axon regeneration observed in ddr-2 mutants, suggesting that DDR-2 functions upstream of SVH-2 and SHC-1. These results suggest that DDR-2 modulates the SVH-2–JNK pathway via SHC-1. We thus identify two different RTK signaling networks that play coordinated roles in the regulation of axonal regeneration.

C. elegans Tensin Promotes Axon Regeneration by Linking the Met-like SVH-2 and Integrin Signaling Pathways

“…6D; Table 2). Overexpression of mlk-1, svh-2, and ddr-2 does not increase the frequency of axon regeneration in a wild-type background (Li et al, 2012;Hisamoto et al, 2016). These results suggest that TNS-1 functions downstream of DDR-2 and may act on SVH-2 in the regulation of axon regeneration.…”

“…To construct GFP-PAT-3-ICD, a 150 bp DNA fragment encoding the COOH-terminal 49 aa of PAT-3 (corresponding to 761-809 aa) was synthesized and subcloned into the pEGFP-C1 vector (Clontech). The pFLAG-Tpr-SVH-2C, pFLAG-Tpr-SVH-2C(Y890F), pFLAG-Tpr-DDR-2C, Pmyo-2::DsRed monomer, and Punc-25::max-2 plasmids were described previously (Li et al, 2012;Hisamoto et al, 2016;Pastuhov et al, 2016).…”

“…The Punc-25::tns-1 (25 ng/ l), Punc-25::tns-1⌬N (25 ng/l), Punc-25::tns-1(R1071K ) (25 ng/l), Punc-25::tns-1⌬PTB (25 ng/l), Ptns-1::nls::venus (25 ng/l), Pmec-7:: tns-1 (25 ng/l), Punc-25::tns-1s (25 ng/l), Punc-25::hTensin-3 (25 ng/ l), Punc-25::pat-3 (50 ng/l), Phsp::svh-2::gfp (45 ng/l), Punc-25::tns-1::gfp (50 ng/l), and Pmyo-2::DsRed monomer (25 ng/l) plasmids were used in kmEx1243 (Punc-25::tns-1 ϩ Pmyo-2::DsRed monomer), kmEx1244 (Punc-25::tns-1⌬N ϩ Pmyo-2::DsRed monomer), kmEx1245 (Punc-25::tns-1(R1071K ) ϩ Pmyo-2::DsRed monomer), kmEx1246 (Punc-25::tns-1⌬PTB ϩ Pmyo-2::DsRed monomer), kmEx1251 (Ptns-1:: nls::venus ϩ Pmyo-2::DsRed monomer), kmEx1252 (Pmec-7::tns-1 ϩ Pmyo-2::DsRed monomer), kmEx1253/kmEx1267 (Punc-25::tns-1s ϩ Pmyo-2::DsRed monomer), kmEx1256/kmEx1268 (Punc-25::hTensin-3 ϩ Pmyo-2::DsRed monomer), kmEx1266 (Punc-25::pat-3 ϩ Pmyo-2:: DsRed monomer), kmEx1262 (Punc-25::tns-1::gfp ϩ Pmyo-2::DsRed monomer), and kmEx1260 (Phsp::svh-2::gfp ϩ Pmyo-2::DsRed monomer), respectively. The wpIs36 (Punc-47::mcherry), maEx247 (Ppat-3:: mcherry::H2B::pat-3 3ЈUTR ϩ Ppat-3::gfp::H2B::pat-3 mutated 3ЈUTR), kmEx468 (Punc-25::max-2), kmEx507 (Pmlk-1::mlk-1), kmEx1206 (Punc-25::svh-2), and kmEx1202 (Punc-25::ddr-2) transgenes were described previously (Li et al, 2012;Burke et al, 2015;Hisamoto et al, 2016;Pastuhov et al, 2016;Shimizu et al, 2018).…”

“…2A). The svh-4 gene is identical to ddr-2 and encodes a RTK homologous to the mammalian discoidin domain receptor (DDR), which is activated by collagen (Hisamoto et al, 2016). SVH-4/DDR-2 also modulates the SVH-1-SVH-2-JNK pathway ( Fig.…”

The Amyloid Precursor-like Protein APL-1 Regulates Axon Regeneration

“…It has been shown in rats that inhibition of collagen IV deposition at the injury site by antibodies or a drug that inhibits collagen triple helix formation can promote the regeneration of CNS neurons (Stichel et al, 1999). One of the type IV collagens in C. elegans, emb-9, has been found to be required for axon regeneration (Hisamoto et al, 2016). In vitro, collagen IV can promote axon outgrowth by functioning with integrin receptors (Bradshaw et al, 1995;Lein et al, 1991;Venstrom and Reichardt, 1995).…”