CoA

Protein CoAlation:

• reversible PTM where CoA is covalently attached to the cysteine residues via a disulphide bond

Cellular Functions of CoA:

• Central metabolic carrier that mainly transfers acyl groups between pathways:

  • Fatty acid synthesis

  • Energy production

  • Amino acid metabolism

  • Neurotransmitter synthesis

  • PTMs

  • Response to stress

Research on Ribosomal S6 Kinases

• Proteins Studied: S6K1 and S6K2, which are kinases involved in growth and metabolism

• Notable findings from literature:

  • S6K2 (located at 11q13)

  • S6K1 (located at 17q23)

• Literature Reference:

  • (Montagne, 1999)

  • (Shima, 1998)

S6K1/2 Expression in Cancer

• Observations:

  • S6K1/2 overexpression in Small Cell Lung Cancer (SCLC)

  • Increased S6K2 staining correlating with chemoresistance in biopsies (worse treatment response)

Key Milestones in S6K Research

• Development of S6K1 activity assays for screening

• Identification and optimization of potential drug leads targeting S6K pathways

CoA Biosynthesis

• Components of CoA Synthesis:

  • Vitamin B5, Cysteine involvement, and ATP

  • Important Enzymes: Pantothenate kinase (PANK) and CoA synthase

• Pathway Illustration:

  • Starts with B5 and integrates with metabolic precursors through various enzymatic actions.

Role of ROS in Cellular Functions

• Oxidative Damage:

  • Common cellular targets: DNA, lipids, proteins

• Stress Response:

  • Activation of antioxidant responses to counteract oxidative stress

Hypothesis on CoA and Oxidative Stress

• Proposed idea that CoA may protect cells from oxidative and metabolic stresses

Methodologies and Key Reagents

• Specific anti-CoA monoclonal antibodies in immunological assays

• Robust MS-MS methods for identifying CoA-modified proteins

• Establishment of efficient in vitro protein CoAlation and deCoAlation assays

Protein CoAlation Induction

• Key Findings:

  • Protein CoAlation strongly induced by oxidizing agents, such as H2O2

  • Results observed in various cell types including primary cardiomyocytes and perfused rat heart models 灌流心脏

Proteomic Analysis of CoAlated Proteins (which protein is modified by CoA)

• Oxidative stress, lack of glucose increase the amount of protein CoAlation

• Breakdown of CoAlated proteins:

  • 68% involved in metabolic processes → CoAlation mainly targets metabolic proteins

  • 12% of S. aureus gene products responding to oxidative stress

CoAlation's Influence on Protein Activity

• Development of in vitro assays to assess the impact of CoAlation on enzyme activity (e.g., aconitase, CK, GAPDH)

• Findings indicate that CoAlation can inhibit activities of modified enzymes

Kinase Interaction with CoA

• Hypothesize potential binding and inhibition of protein kinases by CoA

Aurora A Kinase Modification by CoA

• Effects of CoA:

  • CoA can covalently modify Aurora A kinase, impacting its activation

  • Critical amino acid Cys290 near Thr288 is targeted during this process

  • Log[CoA (nM)] and IC50 values for competitive binding

Structural Insights into Aurora A/CoA Complex

• Binding analysis demonstrating CoA occupying ATP binding site

• Covalent interactions highlight a dual anchor mode, suggesting mechanisms for inhibition

Functions of Protein CoAlation

• Protection from oxidative stress, regulation of protein activity, changes in conformational states, and modulation of cellular localization

Molecular Dissection of CoAlation Cycle

• Studying CoAlation in relation to pathologies linked with oxidative stress including neurodegeneration and cancer

CoAlation and Neurodegeneration Links

• Examination of CoA pathways and their significance in neurodegenerative diseases

Immunoreactivity Analysis in Diseases

• Investigation of anti-CoA immunoreactivity across various neurodegenerative pathologies using different brain regions as case studies

Summary of CoAlation in Cancer

• Review of CoA profiles in normal liver, cirrhosis, and hepatocellular carcinoma contexts

Binding Protein Analysis

• Techniques utilized for identifying CoA binding proteins across multiple tissue types

NME1 Protein as a Case Study

• Function: NME1 acts as nucleoside diphosphate kinase

• Found to be CoAlated under stress conditions impacting its activity

Model of NME1 CoAlation

• Proposed understanding of how oxidative stress modifies NME1 function through CoA interactions resulting in loss of activity

Take-home Summary

• Insight into CoA roles in metabolism and stress responses, highlighting protein CoAlation's multifaceted biological significance.