SOCS proteins and caveolin-1 as negative regulators of endocrine signaling

Recently, a new class of regulatory molecules has emerged; these molecules, termed SOCS proteins, function as suppressors of cytokine signaling. SOCS proteins negatively regulate the Janus kinase signal transducer and activator of transcription (JAK–STAT) signaling cascade. Interestingly, it appears that other proteins, such as caveolin-1, can also function as suppressors of cytokine signaling by inhibiting the kinase activity of JAK family members. This might result from the ability of caveolin-1 to function as a broad-spectrum kinase inhibitor through the caveolin-scaffolding domain.