CLONING OF THE COMPLETE CODING REGION FOR HUMAN PROTEIN PHOSPHATASE INHIBITOR-2 USING THE 2-HYBRID SYSTEM AND EXPRESSION OF INHIBITOR-2 IN ESCHERICHIA-COLI

The yeast two hybrid system has been employed to identify cDNAs encodi ng proteins which interact with the gamma(1) isoform of human protein phosphatase 1. Here we report the isolation of a cDNA encoding human p rotein phosphatase inhibitor 2. The deduced human sequence of 205 amin o acids shows 92% identity to inhibitor 2 from rabbit. Human inhibitor 2 was expressed in E. coli and purified to homogeneity. The expressed human protein inhibited both native and bacterially expressed PP1, wi th the same K-i(1 nM) as inhibitor 2 purified from skeletal muscle. A gene or pseudogene for inhibitor 2 may be present near the major histo compatibility complex on chromosome 6.