GOLPH3 and glioblastoma: To systematically identify DARS1-AS1–interacting proteins, we performed affinity purification (AP) using an anti-FLAG antibody followed by mass spectrometry (MS) in formaldehyde–cross-linked GBM cells expressing FLAG-tagged bacteriophage MS2 coat protein and MS2 binding site (MS2bs)–tagged sense/antisense sequence of DARS1-AS1 transcript NR_110199.1 (Fig. 4B, Materials and Methods) (10).