Sprouty Homolog 4 (SPRY4)

SPRY4 is an inhibitor of the receptor-transduced mitogen-activated protein kinase (MAPK) signaling pathway. It is positioned upstream of RAS activation and impairs the formation of active GTP-RAS.SPRY4 contains a prototypic cysteine-rich region, 3 potential Src homology-3 (SH3)-binding proline-rich regions, and a PEST sequence. It shares 88% amino acid identity with mouse Spry4. Northern blot analysis detected expression of a 4.9-kb transcript in all tissues examined. Alternative splicing and use of an alternate polyadenylation site results in a 7.0-kb cDNA representing a transcript with a premature stop codon, due to a single-nucleotide shift. The deduced truncated protein contains 106 amino acids, and the transcript contains 5 polyadenylation sites, 9 ATTTA sequences, 2 Alu repeats, and 3 CAGAC motifs.