non-membrane spanning protein tyrosine phosphatase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: non-membrane spanning protein tyrosine phosphate + H2O = non-membrane spanning protein tyrosine + phosphate. [EC:3.1.3.48]

Non-membrane spanning protein tyrosine phosphatase activity refers to the enzymatic function of certain proteins that remove phosphate groups from tyrosine residues within proteins. These enzymes, known as protein tyrosine phosphatases (PTPs), play crucial roles in regulating a wide range of cellular processes, including signal transduction, cell growth, differentiation, and metabolism.

Here's a detailed breakdown of their molecular function:

* **Substrate Specificity:** PTPs specifically target phosphotyrosine residues, which are phosphorylated tyrosine amino acids within protein substrates. This specificity arises from the active site of the enzyme, which is designed to recognize and interact with the phosphotyrosine group.

* **Catalytic Mechanism:** PTPs employ a two-step catalytic mechanism involving a conserved cysteine residue in their active site.
* **Step 1:** The cysteine residue attacks the phosphate group of the phosphotyrosine, forming a phospho-cysteine intermediate.
* **Step 2:** A water molecule then attacks the phospho-cysteine intermediate, releasing the inorganic phosphate and regenerating the active site cysteine.

* **Regulation:** The activity of PTPs is tightly regulated through various mechanisms, including:
* **Protein-protein interactions:** Interactions with other proteins can modulate PTP activity by affecting their localization, substrate accessibility, or catalytic efficiency.
* **Post-translational modifications:** Phosphorylation, acetylation, and other modifications can alter the activity of PTPs.
* **Redox regulation:** Some PTPs are sensitive to changes in cellular redox state, which can influence their catalytic activity.

* **Cellular Roles:** PTPs are involved in diverse cellular processes, including:
* **Signal Transduction:** PTPs act as "off-switches" in signaling pathways, counteracting the effects of protein tyrosine kinases (PTKs). They dephosphorylate tyrosine residues on signaling proteins, terminating or modulating downstream signaling events.
* **Cell Growth and Differentiation:** PTPs regulate cell growth, proliferation, and differentiation by controlling the activity of key signaling molecules involved in these processes.
* **Metabolism:** PTPs are involved in regulating metabolic pathways, including glucose metabolism and insulin signaling.
* **Immune Response:** PTPs play crucial roles in immune cell function and inflammation.

* **Non-Membrane Spanning:** This descriptor indicates that these PTPs lack a transmembrane domain and are therefore located within the cytoplasm or nucleus, rather than being embedded in the cell membrane.

The diverse functions and regulatory mechanisms of PTPs highlight their critical roles in maintaining cellular homeostasis and orchestrating various biological processes.'
"

Proteins (13)

Compounds (240)