InterPro domain: IPR009079

This superfamily contains a domain with a core structure consisting of a closed bundle of four helices in a left-handed twist, with two crossover connections. Proteins containing this domain include long-chain cytokines, such as leukaemia inhibitory factor (LIF) [ 1 ], the growth hormone somatotropin [ 2 ], interleukin-6 [ 3 ] and leptin [ 4 ]; short-chain cytokines, such as erythropoietin [ 5 ], stem cell factor (SCF) [ 6 ], macrophage colony-stimulating factor (M-CSF) and interleukin-2, -3, -4, -5, -13, -15 and -21; and interferons/interleukin-10.

1. Gene expression of leukemia inhibitory factor (LIF) and macrophage colony stimulating factor (M-CSF) in bovine endometrium during early pregnancy. Theriogenology 60, 1217-26
2. Somatostatin receptors. Biochim. Biophys. Acta 1616, 1-84
3. 1.9 A crystal structure of interleukin 6: implications for a novel mode of receptor dimerization and signaling. EMBO J. 16, 989-97
4. Crystal structure of the obese protein leptin-E100. Nature 387, 206-9
5. NMR structure of human erythropoietin and a comparison with its receptor bound conformation. Nat. Struct. Biol. 5, 861-6
6. Structure of the active core of human stem cell factor and analysis of binding to its receptor kit. EMBO J. 19, 3192-203