OIP5 and gastric cancer: Additionally, OIP5-AS1-knockdown cells had increased hnRNPA1 ubiquitination levels, but OIP5-AS1-overexpressing cells displayed decreased hnRNPA1 ubiquitination levels (Fig. 8I), indicating that OIP5-AS1 is involved in the proteasome-dependent degradation of hnRNPA1 in GC cells.