MAPK1 and schizophrenia: In this article, we reported that ERVWE1 amplified the expression of HTR1B, p-ERK1/2, p-ELK1, and Arc in SH-SY5Y cells and 5-HT neurons, indicating that ERVWE1 could upregulate Arc expression through the ERK cascade, thus potentially participating in the development of schizophrenia.