9O7V

Crystal Structure of the RIb:C Heterodimer of PKA

9O7V の概要

• エントリーDOI: 10.2210/pdb9o7v/pdb
• 分子名称: cAMP-dependent protein kinase catalytic subunit alpha, cAMP-dependent protein kinase type I-beta regulatory subunit (2 entities in total)
• 機能のキーワード: camp-dependent protein kinase, regulatory subunit, n3a motif, allosteric crosstalk, transferase
• 由来する生物種: Mus musculus (house mouse); 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 83788.20

構造登録者

Wu, J.,Ilouz, R.,Taylor, S.S. (登録日: 2025-04-15, 公開日: 2025-10-29)

主引用文献

Wu, J.,Bruystens, J.G.H.,Sahoo, P.,Bubis, J.,Maillard, R.A.,Taylor, S.S.,Ilouz, R.
N3A motifs in RI beta mediate allosteric crosstalk between cAMP and ATP in PKA activation.
Protein Sci., 34:e70332-e70332, 2025

PubMed Abstract: The RIβ subunit of cAMP-dependent protein kinase (PKA) is highly expressed in the brain, yet it remains the least studied of the PKA regulatory subunits (R). As pathologic variants of its gene are increasingly implicated in neurodevelopmental disorders, neurodegeneration, and cancer, gaining more information about the structure/function of RIβ, and how it differs from RIα, has become increasingly important. We previously reported the structure of the RIβC holoenzyme, which revealed a novel conformation where ATP binding was stabilized by a head-to-head anti-parallel packing of the C-tail wrapped around the N-lobe of the catalytic subunit (C). Although visible, the Dimerization/Docking Domain was poorly folded and reduced. Since RIβ is oxidized in brain tissues, we asked if oxidation or binding of an A Kinase Anchoring Protein (AKAP) would affect the holoenzyme structure. Oxidation or addition of an AKAP peptide to crystals led to the release of nucleotide. To capture this at higher resolution we crystallized RIβC in the presence of an AKAP peptide. This new structure represents an RIβ:C heterodimer. Density for the D/D domain was missing; ATP was absent, the kinase adopted an open conformation, and the C-terminus of the RIβ subunit was no longer resolved. Because the crosstalk between ATP and cAMP in the R:C complex appears to be mediated by the two N3A motifs (N3A and N3A) as well as by the linker, which in free RIβ is intrinsically disordered, we describe the conserved features of these two motifs as well as the linker and show how each contributes in a unique but coordinated way to allosteric activation of RIβ holoenzymes by cAMP. A key difference in our RIβ:C structure is the rotation of the side chain of W260 at the N-terminus of the αA Helix in N3A. W260, at the R:C interface in the holoenzyme, is also the capping residue for cAMP bound to CNB-A, so we may have actually captured the first step in cAMP activation.

PubMed: 41108566
DOI: 10.1002/pro.70332

実験手法

X-RAY DIFFRACTION (3.7 Å)