Interfacial Partitioning of a Loop Hinge Residue Contributes to Diacylglycerol Affinity of Conserved Region 1 Domains

Abstract

Background:The activity of protein kinase C isoenzymes (PKCs) is regulated by diacylglycerol (DAG). Results: Aromatic residue that tunes DAG affinity influences the recruitment of the conserved region 1 (C1) regulatory domain to a membrane mimic. Conclusion: Membrane pre-association step contributes to the affinity of C1 to diacylglycerol. Significance: This work offers insight into the origin of differential DAG affinities in PKCs.

Toggling of Diacylglycerol Affinity Correlates with Conformational Plasticity in C1 Domains

“…For the wtC1Bδ/W252Y pair, the Trp at the hinge position enhances protein-micelle interactions ~15-fold in the absence of DAG. 12 The wtC1Bα/Y123W pair qualitatively shows a similar trend. 9 Therefore, stronger interactions of Trp-containing variants with membranes are one factor that contributes to the correlation between the residue identity and DAG affinity.…”

“…10,11 The DAG-toggling effect of the W252Y mutation has been demonstrated for C1Bδ in lipid bilayers 8 and micelles. 12 …”

Dynamics and Membrane Interactions of Protein Kinase C

“…The preferential partitioning of the β34 Trp into the hydrophobic environment was later demonstrated by us quantitatively for the wtC1Bδ/W252Y pair ( vide infra ). 75 …”

“…75 A paramagnetic agent, the doxyl-labeled lipid, was incorporated into the mixed DPS/DPC micelles either in the absence or presence of short-chain diacylglycerol, 1,2-dioctanoyl-sn-glycerol (DOG). The principle behind PRE-based experiments is that the cross-peaks of protein residues penetrating into the hydrophobic core of the micelles will be broadened, due to the efficient relaxation caused by an unpaired electron.…”

“…C1 domains and their ligands (adapted from 75 ). (A) Primary and tertiary structure of C1Bδ complexed to phorbol-13 acetate, P13A (PDB ID 1PTR 85 ).…”