Regulator that plays a central role in regulation of apoptosis and transcription via its interaction with NF-kappa-B and p53/TP53 proteins. Blocks transcription of HIV-1 virus by inhibiting the action of both NF-kappa-B and SP1. Also inhibits p53/TP53 function, possibly by preventing the association between p53/TP53 and ASPP1 or ASPP2, and therefore suppressing the subsequent activation of apoptosis (PubMed:12524540). Is involved in NF-kappa-B dependent negative regulation of inflammatory response (PubMed:28069640). {ECO:0000269|PubMed:10336463, ECO:0000269|PubMed:12134007, ECO:0000269|PubMed:12524540, ECO:0000269|PubMed:15489900, ECO:0000269|PubMed:28069640}. This is the function of PPP1R13L (protein phosphatase 1 regulatory subunit 13 like, ENSG00000104881).