Related Experiment Video

Updated: Jun 23, 2026

Identification of Kinase-substrate Pairs Using High Throughput Screening
11:13

Identification of Kinase-substrate Pairs Using High Throughput Screening

Published on: August 29, 2015

Cushing's syndrome driver mutation disrupts protein kinase A allosteric network, altering both regulation and

Caitlin Walker1, Yingjie Wang1,2, Cristina Olivieri1

  • 1Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.

Science Advances
|September 7, 2019
PubMed

Insights

A mutation in the PRKACA gene (PKA-C) causes Cushing's syndrome by disrupting enzyme regulation and altering substrate specificity, leading to adrenocortical adenomas.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Endocrinology

Background:

  • Genetic alterations in the PRKACA gene are associated with cortisol-secreting adrenocortical adenomas and Cushing's syndrome.
  • A specific mutation, L205R, is frequently identified in patients with these conditions.
  • The structural similarity between wild-type and mutant PKA-C hinders understanding of the mutation's functional impact.

Purpose of the Study:

  • To elucidate the molecular mechanism by which the PKA-C L205R mutation leads to aberrant enzyme function.
  • To investigate the disruption of the allosteric network and its consequences on enzyme regulation and substrate specificity.

Main Methods:

  • Nuclear Magnetic Resonance (NMR) spectroscopy
  • Thermodynamic analyses
  • Kinetic assays
  • Molecular dynamics simulations

Main Results:

  • The L205R mutation induces global changes in the PKA-C enzyme, disrupting its intramolecular allosteric network.
  • Loss of nucleotide/pseudo-substrate binding cooperativity was observed in the mutant kinase.
  • The mutated PKA-C (PKA-C^L205R) exhibits altered substrate specificity, phosphorylating non-canonical substrates due to a rewired allosteric network.

Conclusions:

  • The PKA-C L205R mutation disrupts enzyme regulation and alters substrate specificity, contributing to the pathogenesis of cortisol-secreting adrenocortical adenomas.
  • Understanding these molecular changes provides insight into the development of Cushing's syndrome.

More Related Videos

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer06:51

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer

Published on: July 21, 2018

Identification of Novel CK2 Kinase Substrates Using a Versatile Biochemical Approach11:11

Identification of Novel CK2 Kinase Substrates Using a Versatile Biochemical Approach

Published on: February 21, 2019

Related Concept Videos

mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
Cushing Syndrome I: Introduction01:26

Cushing Syndrome I: Introduction

Cushing syndrome refers to the collection of clinical manifestations that arise when tissues are exposed to excessive amounts of cortisol or cortisol-like medications over an extended period. Cortisol, a glucocorticoid produced by the adrenal cortex, regulates metabolism, immune responses, and the body’s adaptation to stress. When its concentration remains chronically elevated, these physiological pathways become dysregulated, resulting in the characteristic features of the syndrome.Exogenous...
Cushing Syndrome II: Pathophysiology01:19

Cushing Syndrome II: Pathophysiology

Cortisol production is normally governed by the hypothalamic–pituitary–adrenal (HPA) axis, which maintains hormonal balance through tightly regulated feedback mechanisms. Disruption of this regulatory system is central to the development of Cushing syndrome, whether the excess cortisol originates from external medications or internal pathology. Persistent cortisol elevation alters metabolism, immune function, and endocrine signaling, producing the characteristic clinical features of the...