Transmembrane tyrosine phosphatase, nucleic acids encoding the same, and

Abstract

The present invention relates to regulation and control of cellular processes by transmembrane protein tyrosine phosphatases, and to ligands that agonize or antagonize tyrosine phosphorylation mediated by such tyrosine phosphatases. This invention further relates to diagnosis and therapy based on the activity of such ligands. In particular, the invention provides a novel transmembrane protein tyrosine phosphatase-.lambda. (PTP.lambda.), nucleic acids encoding the same, antibodies to the PTP.lambda., and methods for identifying ligands to the PTP.lambda. of the invention. A specific Example describes the isolation and characterization of the first chicken transmembrane PTP, called ChPTP.lambda.. It has a unique extracellular domain containing a Ser/Thr/Pro-rich region, spectrin-like repeats, a fibronectin III domain, and an alternatively spliced N-terminus. The expression of ChPTP.lambda. in various tissues and cells was also examined. ChPTP.lambda. was shown to have a tyrosine-specific phosphatase activity, and the basic characteristics of this enzyme were studied.