The function of HNRNPL (heterogeneous nuclear ribonucleoprotein L, ENSG00000104824) is as follows. Splicing factor binding to exonic or intronic sites and acting as either an activator or repressor of exon inclusion. Exhibits a binding preference for CA-rich elements (PubMed:11809897, PubMed:22570490, PubMed:24164894, PubMed:25623890, PubMed:26051023). Component of the heterogeneous nuclear ribonucleoprotein (hnRNP) complexes and associated with most nascent transcripts (PubMed:2687284). Associates, together with APEX1, to the negative calcium responsive element (nCaRE) B2 of the APEX2 promoter (PubMed:11809897). As part of a ribonucleoprotein complex composed at least of ZNF827, HNRNPK and the circular RNA circZNF827 that nucleates the complex on chromatin, may negatively regulate the transcription of genes involved in neuronal differentiation (PubMed:33174841). Regulates alternative splicing of a core group of genes involved in neuronal differentiation, likely by mediating H3K36me3-coupled transcription elongation and co-transcriptional RNA processing via interaction with CHD8. {ECO:0000269|PubMed:11809897, ECO:0000269|PubMed:22570490, ECO:0000269|PubMed:25623890, ECO:0000269|PubMed:26051023, ECO:0000269|PubMed:2687284, ECO:0000269|PubMed:33174841, ECO:0000269|PubMed:36537238}.