obsolete suppression by virus of host STAT1 activity by negative regulation of STAT1 tyrosine phosphorylation true The reason for obsoleting this term is that it is too specific. The exact molecular roles of the individual proteins should be captured separately. inhibition by virus of tyrosine phosphorylation of STAT1 OBSOLETE. Any process in which a virus stops, prevents, or reduces the frequency, rate or extent of host STAT1 (signal transducer and activator of transcription-1) activity by stopping, preventing, or reducing the frequency, rate or extent of the introduction of a phosphate group to a tyrosine residue of a STAT1 protein. For example, the measles virus V protein inhibits tyrosine phosphorylation of STAT1, thereby preventing STAT1 activation. biological_process 2012-03-12T04:50:38Z bf GO:0039571