There are 8 protein members of the SOCS family: cytokine-inducible SH2 domain-containing protein (CISH), SOCS1, SOCS2, SOCS3, SOCS4, SOCS5, SOCS6, and SOCS7, each protein has an SH2 domain and a 40-amino-acid region called the SOCS box.[48] The SOCS box can interact with a number of proteins to form a protein complex, and this complex can then cause the breakdown of JAKs and the receptors themselves, therefore inhibiting JAK-STAT signalling.[2] The protein complex does this by allowing a marker called ubiquitin to be added to proteins, in a process called ubiquitination, which signals for a protein to be broken down.[49] The proteins, such as JAKs and the receptors, are then transported to a compartment in the cell called the proteasome, which carries out protein breakdown.[49]