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Dynamics of the interaction between the insulin receptor and protein tyrosine-phosphatase 1B in living cells.

ABSTRACT: The dynamics of the interaction of the insulin receptor with a substrate-trapping mutant of protein-tyrosine phosphatase 1B (PTP1B) were monitored in living human embryonic kidney cells using bioluminescence resonance energy transfer (BRET). Insulin dose-dependently stimulates this interaction, which could be followed in real time for more than 30 minutes. The effect of insulin on the BRET signal could be detected at early time-points (30 seconds), suggesting that in intact cells the tyrosine-kinase activity of the insulin receptor is tightly controlled by PTP1B. Interestingly, the basal (insulin-independent) interaction of the insulin receptor with PTP1B was much weaker with a soluble form of the tyrosine-phosphatase than with the endoplasmic reticulum (ER)-targeted form. Inhibition of insulin-receptor processing using tunicamycin suggests that the basal interaction occurs during insulin-receptor biosynthesis in the ER. Therefore, localization of PTP1B in this compartment might be important for the regulation of insulin receptors during their biosynthesis.

SUBMITTER: Boute N

PROVIDER: S-EPMC1315895 | biostudies-literature | 2003 Mar

REPOSITORIES: biostudies-literature

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Dynamics of the interaction between the insulin receptor and protein tyrosine-phosphatase 1B in living cells.

Boute Nicolas N Boubekeur Samira S Lacasa Danièle D Issad Tarik T

EMBO reports 20030301 3

The dynamics of the interaction of the insulin receptor with a substrate-trapping mutant of protein-tyrosine phosphatase 1B (PTP1B) were monitored in living human embryonic kidney cells using bioluminescence resonance energy transfer (BRET). Insulin dose-dependently stimulates this interaction, which could be followed in real time for more than 30 minutes. The effect of insulin on the BRET signal could be detected at early time-points (30 seconds), suggesting that in intact cells the tyrosine-ki ...[more]

PMID: 12634852

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Project description:A new paradigm in metallobiochemistry describes the activation of inactive metalloenzymes by metal ion removal. Protein tyrosine phosphatases (PTPs) do not seem to require a metal ion for enzymatic activity. However, both metal cations and metal anions modulate their enzymatic activity. One binding site is the phosphate binding site at the catalytic cysteine residue. Oxyanions with structural similarity to phosphate, such as vanadate, inhibit the enzyme with nanomolar to micromolar affinities. In addition, zinc ions (Zn2+) inhibit with picomolar to nanomolar affinities. We mapped the cation binding site close to the anion binding site and established a specific mechanism of inhibition occurring only in the closed conformation of the enzyme when the catalytic cysteine is phosphorylated and the catalytic aspartate moves into the active site. We discuss this dual inhibition by anions and cations here for PTP1B, the most thoroughly investigated protein tyrosine phosphatase. The significance of the inhibition in phosphorylation signaling is becoming apparent only from the functions of PTP1B in the biological context of metal cations as cellular signaling ions. Zinc ion signals complement redox signals but provide a different type of control and longer lasting inhibition on a biological time scale owing to the specificity and affinity of zinc ions for coordination environments. Inhibitor design for PTP1B and other PTPs is a major area of research activity and interest owing to their prominent roles in metabolic regulation in health and disease, in particular cancer and diabetes. Our results explain the apparent dichotomy of both cations (Zn2+) and oxyanions such as vanadate inhibiting PTP1B and having insulin-enhancing ("anti-diabetic") effects and suggest different approaches, namely targeting PTPs in the cell by affecting their physiological modulators and considering a metallodrug approach that builds on the knowledge of the insulin-enhancing effects of both zinc and vanadium compounds.

Dataset Information

Dynamics of the interaction between the insulin receptor and protein tyrosine-phosphatase 1B in living cells.

Publications

Dynamics of the interaction between the insulin receptor and protein tyrosine-phosphatase 1B in living cells.

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