activation of protein kinase activity

Definition

Target type: biologicalprocess

Any process that initiates the activity of an inactive protein kinase. [GOC:mah]

Protein kinase activation is a fundamental process in cellular signaling, regulating a vast array of biological processes. It involves the conversion of an inactive protein kinase into an active form capable of catalyzing the phosphorylation of target proteins. This activation is typically achieved through a series of molecular events that can be broadly categorized into two main mechanisms: **1. Conformational Changes:** Many protein kinases are regulated by changes in their three-dimensional structure. These conformational changes can be triggered by various factors, including: * **Binding of regulatory proteins:** Some protein kinases are associated with inhibitory proteins that prevent their activity. The binding of an activating protein or the removal of the inhibitory protein can induce a conformational change that exposes the active site of the kinase. * **Post-translational modifications:** Modifications like phosphorylation, acetylation, or ubiquitination can alter the conformation of a kinase, either activating or inhibiting its activity. * **Ligand binding:** Some protein kinases are activated by the binding of specific ligands, such as hormones, growth factors, or other signaling molecules. **2. Substrate Recognition and Binding:** Once activated, protein kinases need to bind to their specific substrates, the proteins they will phosphorylate. * **Substrate specificity:** Protein kinases exhibit a high degree of substrate specificity, meaning they typically only phosphorylate a limited set of proteins. This specificity is determined by the structure of the kinase and the recognition motifs present in its substrates. * **Phosphorylation sites:** Within a substrate protein, specific amino acid residues are targeted for phosphorylation. These residues are typically located in short linear motifs known as phosphorylation sites. **The overall process of protein kinase activation can be summarized as follows:** 1. An inactive protein kinase exists in a conformation that masks its active site. 2. An activating signal triggers a conformational change in the kinase, exposing its active site. 3. The activated kinase binds to its specific substrate. 4. The kinase transfers a phosphate group from ATP to a specific amino acid residue in the substrate, resulting in phosphorylation. The phosphorylation event can have a variety of effects on the substrate protein, including: * **Activation or inhibition:** Phosphorylation can either activate or inhibit the activity of the substrate protein. * **Altering protein interactions:** Phosphorylation can create or disrupt interactions between proteins, influencing their localization and function. * **Promoting protein degradation:** Phosphorylation can target proteins for degradation by the proteasome. Protein kinase activation is a tightly regulated process that is essential for maintaining cellular homeostasis and responding to external stimuli. Dysregulation of protein kinase activity can lead to various diseases, including cancer and metabolic disorders.'
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Proteins (11)

Compounds (1,134)