Protein Kinase A: Difference between revisions
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Protein Kinase A (PKA) helps animals cope with stressful situations. In the "flight or fight" response, muscle becomes primed for action as a result of the activity of PKA. Upon activation by cAMP, PKA alters the activities of target proteins by phopshorylating specific serine or threonine residues. | Protein Kinase A (PKA) helps animals cope with stressful situations. In the "flight or fight" response, muscle becomes primed for action as a result of the activity of PKA. Upon activation by cAMP, PKA alters the activities of target proteins by phopshorylating specific serine or threonine residues. | ||
== Structure == | |||
PKA consists of two types of subunits. It has a 49-kd regulatory subunit (R) and a 38-kd catalytic subunit (C).When PKA is enzymatically inactive (absence of cAMP), it is a tetrameric complex of a regulatory dimer bound to two catalytic subunits, forming the R2C2 complex. In its active state, the complex dissociates to form an R2 subunit and two C subunits. The catalytic subunit has two lobes. The larger lobe binds the peptide and contributes the key catalytic residues and the smaller lobe makes many contacts with ATP-Mg2+. | |||
== Mechanism == | == Mechanism == | ||
