CAMP Dependent Protein Kinase, Catalytic Subunit

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Contents 1 Introduction 2 General Domain Structure 3 Activation and Interaction with Regulatory Subunit 4 References

Introduction

The catalytic subunit of PKA is model kinase that is very well characterized because of its catalytic and structural simplicity and ease of Isolation. PKA is essential to cellular signalling in eukaryotes and is involved in a myriad of different processes depending on cell type. PKA catalyzes the transfer of a gamma-phosphoryl group of a molecule of ATP to either a serine or threonine residue on the target protein. This post-translational modification can serve to alter the function of the phosphorylated target protein.

spinqualitylabelsall models PDB ID 1j3h Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
1j3h, resolution 2.90Å ()
Ligands:
Non-Standard Residues:	, ,
Activity:	Non-specific serine/threonine protein kinase, with EC number 2.7.11.1
Related:	1l3r, 1ctp, 1cmk, 1atp, 1bkx
Structural annotation: Resources: CATH : 1J3Ha02, 1J3Ha01, 1J3Hb02, 1J3Hb01 InterPro : Ipr000719, Ipr011009, Ipr002290, Ipr008271, Ipr000961 Pfam : PF00433, PF00069 SCOP : d1j3ha_, d1j3hb_ UniProt : P05132
Functional annotation: Cellular component: neuromuscular junction cytoplasm mitochondrion nucleus plasma membrane Biological process: protein amino acid phosphorylation mesoderm formation Molecular function: cAMP-dependent protein kinase activity transferase activity protein binding nucleotide binding ATP binding protein kinase activity protein serine/threonine kinase activity kinase activity
Evolutionary conservation: Toggle Conservation Colors: Rows = identical sequences: Further Information: Caveats, Explanation, Complete Results at ConSurfDB
Resources:	FirstGlance, OCA, RCSB, PDBsum
Coordinates:	save as pdb, mmCIF, xml

General Domain Structure

The catallytic subunit of PKA consists of a that is characteristic of many kinases throughout nature. The upper N-terminal lobe of the kinase is dominated by beta-sheet architecture while the lower, larger C-term is mostly alpha helical. Located in between the two lobes is the

Activation and Interaction with Regulatory Subunit

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In the inactive state, the catalytic subunit of PKA exists as a heterotetramer with two regulatory subunits and two catalytic subunits. Regulatory subunits often interact with A Kinase Anchoring proteins that serve to localize a population of PKA in a certain cellular environment, priming a particular response. Upon, cAMP binding to the regulatory domain of PKA (two molecules of cAMP per regulatory subunit) the catalytic subunit is released from the holoenzyme complex and is free to diffuse and exhibit its catalytic activity. Two of the most important residues for this docking interaction are and which both sit in the nucleotide binding region (Phosphate Binding Cassette) of the regulatory subunit. In essence, when a cAMP molecule binds to these trp and tyr binding sites, the docking interaction is ablated. This shows a different representation.^[1]

References

1. ↑ Kim C, Cheng CY, Saldanha SA, Taylor SS. PKA-I holoenzyme structure reveals a mechanism for cAMP-dependent activation. Cell. 2007 Sep 21;130(6):1032-43. PMID:17889648 doi:10.1016/j.cell.2007.07.018