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Program in Molecular Medicine

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Amino Acids, Peptides, and Proteins | Cardiology | Cardiovascular Diseases | Cellular and Molecular Physiology | Enzymes and Coenzymes


cGMP-dependent protein kinase 1alpha (PKG1alpha) promotes left ventricle (LV) compensation after pressure overload. PKG1-activating drugs improve heart failure (HF) outcomes but are limited by vasodilation-induced hypotension. Signaling molecules that mediate PKG1alpha cardiac therapeutic effects but do not promote PKG1alpha-induced hypotension could therefore represent improved therapeutic targets. We investigated roles of mixed lineage kinase 3 (MLK3) in mediating PKG1alpha effects on LV function after pressure overload and in regulating BP. In a transaortic constriction HF model, PKG activation with sildenafil preserved LV function in MLK3+/+ but not MLK3-/- littermates. MLK3 coimmunoprecipitated with PKG1alpha. MLK3-PKG1alpha cointeraction decreased in failing LVs. PKG1alpha phosphorylated MLK3 on Thr277/Ser281 sites required for kinase activation. MLK3-/- mice displayed hypertension and increased arterial stiffness, though PKG stimulation with sildenafil or the soluble guanylate cyclase (sGC) stimulator BAY41-2272 still reduced BP in MLK3-/- mice. MLK3 kinase inhibition with URMC-099 did not affect BP but induced LV dysfunction in mice. These data reveal MLK3 as a PKG1alpha substrate mediating PKG1alpha preservation of LV function but not acute PKG1alpha BP effects. Mechanistically, MLK3 kinase-dependent effects preserved LV function, whereas MLK3 kinase-independent signaling regulated BP. These findings suggest augmenting MLK3 kinase activity could preserve LV function in HF but avoid hypotension from PKG1alpha activation.


Cardiology, Cyclic nucleotides, Heart failure, Hypertension

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Copyright © 2021 Calamaras et al. This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit

DOI of Published Version



Calamaras TD, Pande S, Baumgartner RA, Kim SK, McCarthy JC, Martin GL, Tam K, McLaughlin AL, Wang GR, Aronovitz MJ, Lin W, Aguirre JI, Baca P, Liu P, Richards DA, Davis RJ, Karas RH, Jaffe IZ, Blanton RM. MLK3 mediates impact of PKG1α on cardiac function and controls blood pressure through separate mechanisms. JCI Insight. 2021 Sep 22;6(18):e149075. doi: 10.1172/jci.insight.149075. PMID: 34324442; PMCID: PMC8492323. Link to article on publisher's site

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JCI insight


Full author list omitted for brevity. For the full list of authors, see article.

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Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.