JAK2 is a kinase associated with cytokine receptors such as MPL or the erythropoietin receptor essential for signalling these receptors and the V617F mutation results in constitutive signalling and is capable of inducing a disease similar to Vaquez's ployglobulia in mice or the erythropoietin receptor essential for the signalling of these receptors and the V617F mutation results in constitutive signalling and is capable of inducing a disease similar to Vaquez's ployglobulia in mice or the erythropoietin receptor essential for the signalling of these receptors and the V617F mutation results to constitutive signalling and is capable of inducing a disease close to Vaquez's ployglobulia in mice or the erythropoietin receptor essential for signalling these receptors and the V617F mutation results in constitutive signalling and is capable of inducing a disease close to Vaquez's ployglobulia in mice.