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.