Probable ubiquitin-protein ligase which is mainly involved pre-mRNA splicing and DNA repair (By similarity). Component of the MAC complex that probably regulates defense responses through transcriptional control and thereby is essential for plant innate immunity. Protein modification; protein ubiquitination. Homotetramer. Component of the multiprotein assembly MOS4-associated complex (MAC) at least composed of MOS4, CDC5, PRL1 and PRP19 which is related to the PRP19C/Prp19 complex/NTC/Nineteen complex identified in other organisms. Associated with the spliceosome. A number of isoforms are produced. According to EST sequences. Belongs to the WD repeat PRP19 family.