Mechanism of Signal Transduction, focused on Protein Kinase A.

The PKA complex is formed by the association of catalytic and regulatory subunits. The regulatory subunit has a modular organization composed of a flexible linker domain followed by two cAMP binding domains in tandem (see figure below). The activation of PKA by cAMP binding unleashes numerous allosteric events throughout the entire PKA complex, including ligand binding cooperativity between the cAMP binding domains, a dramatic conformational change in the regulatory subunit, and the dissociation of the complex into catalytic and regulatory subunits.

In the Maillard lab, we use single molecule optical tweezers to dissect the energetics associated with intra- and inter-subunit interactions in PKA, and determine how these energetic networks are modulated by cAMP. Optical tweezers are uniquely suited for these studies because they can selectively manipulate, probe and monitor the response of a specific domain in PKA, in real time, and in the presence of other interacting domains.  Learn more about how we use optical tweezers here.

This project is conducted in collaboration with Dr. Susan Taylor from the University of California, San Diego.


Hao Y, England JP, Bellucci L, Paci E, Hodges HC, Taylor SS, Maillard RA. (2019) Activation of PKA via asymmetric allosteric coupling of structurally conserved cyclic nucleotide binding domains. Nat Commun 10, 3984

England JP, Hao Y, Bai L, Glick V, Hodges HC, Taylor SS, Maillard RA. (2018) Switching of the folding-energy landscape governs the allosteric activation of protein kinase A. Proc Natl Acad Sci U S A 115 (32): E7478-E7485

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