STRAP (serine/threonine kinase receptor associated protein) functions as a regulatory protein involved in multiple cellular processes, most notably as a negative regulator of TGF-β signaling pathways 1. The protein lacks intrinsic enzymatic activity but exerts its biological effects through protein-protein interactions 1. STRAP has been identified as having oncogenic properties, with overexpression correlating with various cancers 1. Mechanistically, STRAP can interact with key signaling proteins such as MEK1/2, leading to activation of ERK/MAPK pathways that promote tumor growth and metastasis 2. In intrahepatic cholangiocarcinoma, STRAP binding to circPCNXL2 enhances its interaction with MEK1/2, resulting in ERK pathway activation and subsequent tumor progression 2. Beyond its role in TGF-β signaling, STRAP appears to regulate multiple distinct cellular processes and modulate various signaling pathways 1. The protein's clinical significance lies primarily in cancer biology, where its overexpression serves as both a potential biomarker and therapeutic target 2. However, the full spectrum of STRAP's biological functions continues to emerge, suggesting it may have broader cellular roles beyond its initially characterized TGF-β inhibitory function 1.