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Apela exhibits isoform- and headgroup-dependent modulation of micelle binding, peptide conformation and dynamics. Biochim Biophys Acta Biomembr 2017 May;1859(5):767-778



Pubmed ID




Scopus ID

2-s2.0-85012000362 (requires institutional sign-in at Scopus site)   25 Citations


Apela (also referred to as ELABELA and toddler) is a peptide hormone that activates the apelin receptor (AR or APJ) to regulate cardiovascular system development and function. Here, we report the first biophysical characterization of three apela isoforms, apela-54, -32, and -11, alongside a monomeric C1S-apela-11 mutant, using circular dichroism (CD) spectropolarimetry and nuclear magnetic resonance (NMR) spectroscopy. The behaviour of apela-54 is consistent with a preprotein containing a hydrophobic, N-terminal signal peptide. The potential for apela-membrane binding, leading to membrane catalyzed interactions with AR, was tested comprehensively for apela-32 and -11 in the presence of membrane-mimetic dodecylphosphocholine (DPC), sodium dodecyl sulfate (SDS), and 1-palmitoyl-2-hydroxy-sn-glycero-3-[phospho-rac-(1-glycerol)] (LPPG) micelles. According to pulsed-field gradient diffusion NMR experiments, apela-32 interacts with all three micelles. Chemical shift perturbations indicate widespread interactions along apela, with DPC and LPPG micelles inducing short segments with α-helical character at distinct regions. Consistent with these data, ps-ns dynamics along the peptide backbone appear decreased in the presence of micelles. Apela-11 and C1S-apela-11, alternatively, interact preferentially with SDS and LPPG micelles, promoting β-turn character observable by CD. Distinct differences in membrane-interaction propensity are therefore apparent both as a function of apela isoform and of detergent headgroup. These results imply the potential for cell membrane involvement in apela-AR recognition and binding, with the implication that membrane catalysis has distinct functional and regulatory roles throughout the apelinergic system.

Author List

Huang SK, Shin K, Sarker M, Rainey JK


Kyungsoo Shin PhD Assistant Professor in the Biophysics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Circular Dichroism
Magnetic Resonance Spectroscopy
Peptide Hormones
Protein Conformation
Protein Isoforms
Protein Structure, Secondary