The R-spondin (RSPO) family is a small group of four secreted proteins (RSPO1-RSPO4) that have pleiotropic functions in development and stem cell growth by strongly enhancing Wnt pathway activation. They contain an N-terminal secretory signal peptide sequence, two tandem furin-like cysteine-rich (Fu-CRD) domains, a thrombospondin type I repeat (TSP) domain, and a C-terminal basic amino acid-rich (BR) domain. Leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4), LGR5, and LGR6 have been identified as receptors for RSPOs [].This entry represents the two tandem furin-like cysteine-rich domains found in R-spondin.
RSPO3 is a secreted protein that belongs to the R-spondin (RSPO) family. Interestingly, it is one of the two members (RSPO2 and RSPO3) of the family capable of potentiating WNT signaling in cells lacking all three LGRs (Leucine-rich repeat-containing G-protein-coupled receptor 4/5/6) []. RSPO3 promotes angioblast and vascular development []. It has been shown to promote bladder cancer progression via mediating the Wnt/beta-catenin and Hedgehog signaling pathways []. The R-spondin (RSPO) family is a small group of four secreted proteins (RSPO1-RSPO4) that have pleiotropic functions in development and stem cell growth by strongly enhancing Wnt pathway activation. They contain an N-terminal secretory signal peptide sequence, two tandem furin-like cysteine-rich (Fu-CRD) domains, a thrombospondin type I repeat (TSP) domain, and a C-terminal basic amino acid-rich (BR) domain. Leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4), LGR5, and LGR6 have been identified as receptors for RSPOs [].
RSPO1 is a secreted protein that belongs to the R-spondin (RSPO) family. It regulates Wnt signalling by inhibiting internalization of LRP6 []. It also regulates the canonical Wnt/beta-catenin-dependent pathway and non-canonical Wnt signalling by acting as an inhibitor of ZNRF3, an important regulator of the Wnt signalling pathway []. The R-spondin (RSPO) family is a small group of four secreted proteins (RSPO1-RSPO4) that have pleiotropic functions in development and stem cell growth by strongly enhancing Wnt pathway activation. They contain an N-terminal secretory signal peptide sequence, two tandem furin-like cysteine-rich (Fu-CRD) domains, a thrombospondin type I repeat (TSP) domain, and a C-terminal basic amino acid-rich (BR) domain. Leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4), LGR5, and LGR6 have been identified as receptors for RSPOs [].
The R-spondin (RSPO) family is a small group of four secreted proteins (RSPO1-RSPO4) that have pleiotropic functions in development and stem cell growth by strongly enhancing Wnt pathway activation. They contain an N-terminal secretory signal peptide sequence, two tandem furin-like cysteine-rich (Fu-CRD) domains, a thrombospondin type I repeat (TSP) domain, and a C-terminal basic amino acid-rich (BR) domain. Leucine-rich repeat-containing G-protein-coupled receptor 4 (LGR4), LGR5, and LGR6 have been identified as receptors for RSPOs [].RSPO2 is a secreted protein that belongs to the R-spondin (RSPO) family. Interestingly, it is one of the two members (RSPO2 and RSPO3) of the family capable of potentiating WNT signaling in cells lacking all three LGRs (Leucine-rich repeat-containing G-protein-coupled receptor 4/5/6) []. It plays a crucial role in limb specification, amplifying the Wnt signaling pathway independently of LGR4-6 receptors, possibly by acting as a direct antagonistic ligand to RNF43 and ZNRF3, hence governing the number of limbs an embryo should form []. It has been shown to promote midbrain dopaminergic neurogenesis and differentiation in human stem cells []. Its structures in complex with the ectodomains of its receptors LGR5 and ZNRF3 have been revealed []. RSPO4 is a secreted protein that belongs to the R-spondin (RSPO) family. It has been associated with embryonic nail development [, ].
