Given the importance of the JAK-STAT signalling pathway, particularly in cytokine signalling, there are a variety of mechanisms that cells possess to regulate the amount of signalling that occurs. Three major groups of proteins that cells use to regulate this signalling pathway are protein inhibitors of activated STAT (PIAS),[26] protein tyrosine phosphatases (PTPs) [27] and suppressors of cytokine signalling (SOCS).[28]