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Updated: Aug 14, 2026

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors
Published on: July 17, 2020
Heterogeneity of hepatic protein tyrosine phosphatases
1Department of Pediatrics, Brown University, Providence, RI.
Abstract:
We have identified multiple members of the protein tyrosine phosphatase family in three subcellular compartments from rat liver; membrane, cytoskeleton and cytosol. Characterization based on substrate specificity, size, and reactivity with an anti-peptide antiserum against human placental PTP1B indicate the presence of at least three PTPases in Triton X-100 extracts of particulate membranes. Of these, one of 600 kDa possesses characteristics of a transmembrane, receptor-like enzyme. A fourth particulate PTPase (70 kDa) represents a distinct cytoskeletal PTPase. Cytosol contains one main PTPase species which was detected as a 41 kDa protein in Western immunoblots. These data indicate the existence of multiple hepatic PTPases whose differences in structure and subcellular localization may reflect functional heterogeneity.
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