SPRY3

SPRY3, or Sprouty homolog 3, is a member of the Sprouty family of intracellular proteins that regulate receptor tyrosine kinase signaling. In humans, SPRY3 is one of several Sprouty genes (SPRY1–SPRY4) that function as negative feedback regulators of signaling pathways activated by growth factors such as fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), and other receptor tyrosine kinases.

The Sprouty family is characterized by conserved regions, including a C-terminal SPR domain that is important for their inhibitory activity. Sprouty proteins are generally localized in the cytoplasm and are thought to interfere with the Ras–MAPK/ERK signaling cascade, thereby dampening cellular responses to RTK activation. The exact molecular interactions can vary among family members, but SPRY proteins are widely considered modulators of RTK signaling.

SPRY3 is located on the X chromosome in humans, and its expression patterns appear to be enriched in neural tissues, with expression that can vary across developmental stages and brain regions. As with other Sprouty proteins, SPRY3’s activity is context-dependent and subject to regulation by cellular signaling states.

In research contexts, SPRY3 and the Sprouty family are studied for their roles in development, neural biology, and cancer, where dysregulation of RTK signaling is a common theme. However, the precise functions and clinical significance of SPRY3 remain to be fully clarified, and the gene is less well characterized than some other Sprouty family members. Sprouty proteins in general are considered important modulators of growth factor–driven signaling pathways across species.