RSPO4

R-spondin 4 is a protein in humans that is encoded by the RSPO4 gene. This gene encodes a member of the R-spondin family of proteins that share a common domain organization consisting of a signal peptide, cysteine-rich/furin-like domain, thrombospondin domain and a C-terminal basic region. The encoded protein may be involved in activation of Wnt/beta-catenin signaling pathways. Mutations in this gene are associated with anonychia congenital. Alternate splicing results in multiple transcript variants.[provided by RefSeq, Sep 2009].

References

Further reading

RSPO2

R-spondin 2 also known as roof plate-specific spondin-2 is a protein that in humans that is encoded by the RSPO2 gene.

R-spondin 2 synergizes with Wnt to activate beta-catenin. RSPO2 has been proposed to regulate craniofacial patterning and morphogenesis within pharyngeal arch 1 through ectoderm-mesenchyme signaling via the endothelin-Dlx5/6 pathway.

In dogs, the Rspo2 gene determines hair growth.

References

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

RSPO1

R-spondin-1 is a secreted protein that in humans is encoded by the Rspo1 gene, found on chromosome 1. In humans, it interacts with WNT4 in the process of female sex development. Loss of function can cause female to male sex reversal. Furthermore, it promotes canonical WNT/β catenin signaling.

Structure

The protein has two cysteine-rich, furin-like domains and one thrombospondin type 1 domain.

Function

Sex Development

Early Gonads

RSPO1 is required for the early development of gonads, regardless of sex. It has been found in mice only eleven days after fertilization. To induce cell proliferation, it acts synergistically with WNT4. They help stabilize β-catenin, which activates downstream targets. If both are deficient in XY mice, there is less expression of SRY and a reduction in the amount of SOX9. Moreover, defects in vascularization are found. These occurrences result in testicular hypoplasia. Male to female sex reversal, however, does not occur because Leydig cells remain normal. They are maintained by steroidogenic cells, now unrepressed.