R-Spondin Signaling in Stem Cell and Cancer Dynamics

R-Spondin (RSPO) proteins are central modulators of the Wnt/β-catenin pathway, orchestrating stem cell maintenance, tissue regeneration and oncogenesis through a finely balanced interplay with leucine-rich repeat G-protein coupled receptors (LGR4/5/6) and transmembrane E3 ubiquitin ligases (ZNRF3/RNF43). In homeostatic niches such as the intestinal crypt, hair follicle, pancreas and selected neural compartments, RSPOs bind LGR receptors and neutralise ZNRF3/RNF43, preventing Wnt receptor degradation and thereby amplifying Wnt signals that drive proliferation and lineage specification. Genetic alterations—including gene fusions or translocations of RSPO2/RSPO3, overexpression of RSPO paralogues or loss-of-function mutations in RNF43/ZNRF3—disrupt this equilibrium, leading to aberrant stem cell expansion, tumour initiation and progression in colorectal, gastric and other cancers. Experimental models demonstrate that tumours harbouring RSPO fusions are strictly dependent on Wnt ligand secretion for growth, revealing a therapeutic window for porcupine inhibitors and direct anti-RSPO strategies. Beyond oncology, RSPOs are being harnessed for regenerative medicine, promoting the neogenesis of pancreatic β cells and enhancing neuronal survival after ischaemic injury. Emerging applications include RSPO-guided drug delivery systems targeting LGR-positive cancer stem cells and the use of RSPO analogues to expand organoids, underscoring the global significance of R-Spondin signalling in both health and disease.

Research from Nature Portfolio

High-resolution structural analyses have delineated how the Furin1–Furin2 domains of RSPO2 engage the ectodomains of ZNRF3 and RNF43. Crystallographic studies revealed that a conserved loop in the Fu1 domain inserts into grooves on the E3 ligase surface, promoting ZNRF3 dimerisation and inhibiting its ubiquitin ligase activity. Comparative assays of all four RSPO paralogues further showed that differential affinities for LGRs and E3 ligases underlie their distinct signalling potencies and tissue specificities, guiding the design of selective modulators for developmental and therapeutic aims. Transgenic mouse models engineered with endogenous EIF3E–RSPO2 or PTPRK–RSPO3 chromosome rearrangements have provided direct evidence that these RSPO fusions are sufficient to initiate crypt hyperplasia and Wnt-dependent intestinal tumours in vivo. Pharmacological blockade of Wnt secretion rapidly cleared these lesions without harming normal crypts, establishing RSPO fusion events as bona fide oncogenic drivers and identifying a clear targetable vulnerability in RSPO-fusion cancers.

R-Spondin Signaling in Stem Cell and Cancer Dynamics publication trend

The graph below shows the total number of articles in r-spondin signaling in stem cell and cancer dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

R-Spondin (RSPO): A family of four secreted proteins that enhance Wnt/β-catenin signalling by binding LGR receptors and antagonising ZNRF3/RNF43.

Wnt/β-catenin signalling: A pathway governing cell proliferation and fate decisions, activated by stabilisation of β-catenin and its nuclear transcriptional functions.

LGR4/5/6: Leucine-rich repeat-containing G-protein coupled receptors that serve as high-affinity receptors for R-Spondins in stem cell niches.

ZNRF3/RNF43: Transmembrane E3 ubiquitin ligases that negatively regulate Wnt signalling by promoting ubiquitination and degradation of Wnt receptors.

Cancer stem cells (CSCs): A subpopulation of tumour cells with self-renewal and differentiation capabilities, implicated in therapy resistance and disease relapse.

References

1. RSPO3 Furin domain-conjugated liposomes for selective drug delivery to LGR5-high cells. Journal of Controlled Release (2023).
2. RSPO1, a potent inducer of pancreatic β cell neogenesis. Cell Reports Medicine (2025).
3. R-spondin-3 promotes proliferation and invasion of breast cancer cells independently of Wnt signaling. Cancer Letters (2023).
4. Endothelial cell-derived RSPO3 activates Gαi1/3-Erk signaling and protects neurons from ischemia/reperfusion injury. Cell Death & Disease (2023).
5. Control of Wnt Receptor Turnover by R-spondin-ZNRF3/RNF43 Signaling Module and Its Dysregulation in Cancer. Cancers (2016).
6. R-Spondin chromosome rearrangements drive Wnt-dependent tumour initiation and maintenance in the intestine. Nature Communications (2017).
7. Structural and molecular basis of ZNRF3/RNF43 transmembrane ubiquitin ligase inhibition by the Wnt agonist R-spondin. Nature Communications (2013).
8. Differential activities and mechanisms of the four R-spondins in potentiating Wnt/β-catenin signaling. Journal of Biological Chemistry (2018).