Isolated and purified proteins and nucleic acids including a novel member of the immunoglobulin super-family characterized as having SHP-2 binding activity and cell signaling activity and called protein zero related or PZR, and cDNA encoding the same. Recombinant host cells, recombinant nucleic acids and recombinant proteins are also disclosed, along with methods of producing each. Isolated and purified antibodies to PZR, and methods of producing the same, are also disclosed. PZR is characterized as having SHP-2 binding activity and cell signaling activity and thus, therapeutic methods involving these activities are also disclosed.