SPOP and prostatitis: Taken together with the absence of consensus SPOP substrate-binding motif Φ−π-S/T-S/T-S/T (Φ: nonpolar residues, π: polar residues) these findings demonstrate that G3BP1 acts as a competitive inhibitor of CUL3SPOP ubiquitin ligase and stabilizes substrates of SPOP, including AR and the AR co-factors (TRIM24 and SRC3), which are drivers of prostate tumorigenesis and its progression.