PIR1, or Dual specificity phosphatase 11, is a human gene encoded by DUSP11. It may also be known as: RNA/RNP complex-1-interacting phosphatase; Dual specificity protein phosphatase 11; Phosphatase that interacts with RNA/RNP complex 1; RNA/RNP complex-1-interacting phosphatase ; RNA/RNP complex 1-interacting; dual specificity phosphatase 11 (RNA/RNP complex 1-interacting). The encoded protein is an enzyme with an amino acid length of 330 and a mass of 38.9 kDa. PIR1 is a member of the Protein-tyrosine phosphatase family, Non-receptor class dual specificity subfamily. Homologs of this gene exist in other organisms, including: Frog.