Ppp2r5a, also known as Protein phosphatase 2, regulatory subunit B (B56), alpha isoform, is a regulatory subunit of the protein phosphatase 2A (PP2A). PP2A is a major member of protein serine/threonine phosphatases in cells. Ppp2r5a can regulate the cellular location, substrate specification, and protein phosphatase function of PP2A, playing a crucial role in many cellular activities [1].

In a mouse model with deletion of the Ppp2r5a gene, loss of the protein phosphatase 2A regulatory subunit PPP2R5A was associated with an increased incidence of stress-induced proarrhythmia. This was evidenced by ECG measurements showing QT time prolongation, more premature ventricular contractions, and increased episodes of ventricular tachyarrhythmia induced by programmed electrical stimulation in knockout mice compared to wild-type animals [2].

In conclusion, Ppp2r5a is essential for regulating the function of PP2A and is involved in various cellular activities. Studies using Ppp2r5a knockout mouse models have revealed its role in cardiac arrhythmogenesis, highlighting its importance in understanding the mechanisms underlying stress-induced proarrhythmia.