STAT1 alpha activation by IL-12 correlated with increased phosphorylation of serine , but not tyrosine .
stat1 alpha activation by il-12 correlated with increased phosphorylation of serine , but not tyrosine .
B-protein_molecule I-protein_molecule O O B-protein_molecule O O O O O B-amino_acid_monomer O O O B-amino_acid_monomer O