Linear representation of STAT5b mutation locations and structure model of STAT5b homodimer. (A) The STAT5b protein domains and localizations of the mutations. Both STAT5b mutations Y665F and N642H are located in the SH2 domain of STAT5b protein. (B) A 3-dimensional model of STAT5b protein structure. The mutations Y665F and N642H are located on the surface of SH2 domain and are colored in purple. F, phenylalanine; H, histidine; N, aspartic acid; and Y, tyrosine.