Sprouty RTK signaling antagonist 3 (SPRY3)

Sprouty RTK signaling antagonist 3 (SPRY3) is an intracellular protein that acts primarily as a **negative regulator of receptor tyrosine kinase (RTK) signaling**, including fibroblast growth factor (FGF) and brain-derived neurotrophic factor (BDNF)-TrkB pathways[3][4][11]. SPRY3 is expressed in neuronal tissues as well as other organs and plays a key role in **developmental processes such as axonal branching, neurite complexity, and tissue morphogenesis**[4][10]. By inhibiting the mitogen-activated protein kinase (MAPK) cascade and calcium signaling, SPRY3 restricts cellular responses to growth factors, modulating branching morphogenesis in both unicellular (neuronal) and multicellular contexts[4]. Unlike other RTK signaling inhibitors, it is classified as an 'antagonist' rather than a typical receptor or enzyme, and there is currently no evidence of SPRY3 being targeted by specific pharmaceuticals. Associations with **intellectual developmental disorders** and possible roles in cancer underscore its biological significance as a regulatory molecule, though its direct therapeutic targeting has not been established[3][2][4].

Other names

Protein sprouty homolog 3Spry-3HSPRY3Sprouty3antagonist of FGF signalingspry-3sprouty homolog 3sprouty3

Not currently targeted directly by drugs; endogenously, SPRY3 inhibits signaling downstream of receptor tyrosine kinases (such as FGF and BDNF-TrkB) by interfering with MAPK/ERK pathway activation and calcium release[3][4]