The activity of Src-kinase is increased when bound to Beta-arrestin-1. The mechanism for this activation is not clear. Src bound to beta -arrestin 1 is substantially dephosphorylated at Tyr530 and this is often associated with Src activation. Binding results with Y530F mutants of Src suggest that binding of Src to arrestin causes a conformational activation of the kinase, rather than a change in phosphorylation. However, increased phosphorylation of Src Tyr419 in cells overexpressing beta-arrestin-1 has been reported to correlate with PAR1 activation, beta-arrestin signalling complex formation, and increased ERK activation.