Serine-threonine kinase receptor-associated protein

STRAP (serine-threonine kinase receptor-associated protein) is a 350-amino acid protein that plays dual roles in RNA processing and signal transduction (UniProt: Q9Y3F4). It participates in the SMN complex, which catalyzes assembly of small nuclear ribonucleoproteins essential for pre-mRNA splicing. Additionally, STRAP negatively regulates TGF-beta signaling while positively enhancing PDPK1 kinase activity through modulation of protein-protein interactions.

STRAP is broadly expressed and functions in the context of spliceosomal biogenesis and cellular distribution of the SMN complex, processes critical for gene expression. The protein also influences transforming growth factor beta pathway signaling, which has implications for cellular differentiation and homeostasis.

STRAP shows reduced abundance in Alzheimer's disease brain tissue. Analysis of post-mortem AD brain versus age-matched controls using TMT-labeled proteomics across four subcellular fractions detected a mean log2 fold-change of −0.18 (Chaparral AD proteomics), indicating modest downregulation. This decrease may relate to altered spliceosomal function or impaired TGF-beta signaling regulation in AD pathology, though the functional consequence remains to be determined.