Recombinant Mouse NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 11 (Ndufa11)

What is the structural composition of NDUFA11 and how does it compare between human and mouse models?

NDUFA11 is a hydrophobic subunit of mitochondrial Complex I (NADH dehydrogenase) with distinct structural domains. The human NDUFA11 gene produces a 15 kDa protein composed of 141 amino acids . The mouse ortholog shares approximately 62% sequence identity with the human version .

The protein has a characteristic two-domain structure:

• N-terminal hydrophobic domain: Forms an alpha helix spanning the inner mitochondrial membrane

• C-terminal hydrophilic domain: Interacts with globular subunits of Complex I

This highly conserved two-domain structure is critical for protein function, with the hydrophobic domain anchoring the NADH dehydrogenase complex at the inner mitochondrial membrane . For optimal experimental design, researchers should consider these structural characteristics when designing expression constructs, particularly ensuring the hydrophobic domain remains intact.

How does NDUFA11 contribute to the assembly and stability of mitochondrial Complex I?

NDUFA11 functions as both a structural component and an intrinsic assembly factor for Complex I. When studying its role:

• NDUFA11 is one of approximately 31 hydrophobic subunits forming the transmembrane region of Complex I

• It serves as an anchor for the NADH dehydrogenase complex at the inner mitochondrial membrane

• Suppression of NDUFA11 expression impairs complex assembly, leading to accumulation of subcomplexes with molecular masses of 550 kDa and 815 kDa

In experimental models, knockdown of NDUFA11 causes:

• Disruption of the respirasome assembly

• Reduced activity of Complexes I, III, and IV

• Decreased ATP production

• Increased mitochondrial ROS production

For valid experimental design, researchers should include appropriate controls that account for these downstream effects when manipulating NDUFA11 expression.

What are the optimal methods for measuring NDUFA11 expression and activity in mouse models?

To effectively quantify NDUFA11 expression and activity:

Expression Analysis:

• Western blot: Use antibodies specific to mouse NDUFA11 at dilutions of 1:1000-1:8000

• RT-PCR: Design primers specific to mouse Ndufa11 mRNA sequence

• Observed molecular weight on blots: 10-15 kDa

Activity Assessment:

• NADH:ubiquinone oxidoreductase (Complex I) activity assay:

  • Isolate mitochondria from mouse tissue (typically liver)

  • Prepare reaction buffer with 50 mM potassium phosphate buffer (pH 7.5), 3 mg/mL fatty acid-free BSA, 300 μM KCN, and 100 μM NADH

  • Initiate reaction with 60 μM ubiquinone

  • Monitor absorbance at 340 nm for 2 minutes

  • Add 10 μM rotenone to discount CI-independent NADH oxidoreductase activity

  • Calculate using NADH extinction coefficient (6.2 mM⁻¹ cm⁻¹)

Protein Interaction Analysis:

• Co-immunoprecipitation (Co-IP): Particularly useful for studying NDUFA11 interactions with other Complex I components, such as NDUFS1

What are the critical considerations when designing siRNA knockdown experiments for Ndufa11?

Based on published research protocols, consider the following when designing Ndufa11 knockdown experiments:

siRNA Design:

• Use at least two different siRNA sequences to confirm specificity

• Validate knockdown efficiency at both mRNA and protein levels

• Published studies achieved 25-33% knockdown using two different siRNAs

Critical Controls:

• Include non-targeting siRNA controls

• Consider rescue experiments with siRNA-resistant constructs

• Monitor cell viability as NDUFA11 knockdown can decrease viability by 41-47%

Experimental Timeline:

• Assess effects 72-96 hours post-transfection

• For mitochondrial function studies, measure oxygen consumption rate using tools like Seahorse XF analyzers

Anticipated Effects:

• Expect reduced Complex I assembly and activity

• Monitor for changes in mitochondrial morphology (potential fragmentation)

• Assess changes in respirasome assembly using Blue Native PAGE

How is NDUFA11 implicated in ischemic stroke models, and what are the best methods to study this connection?

Recent research has identified NDUFA11 as a potential disulfidptosis-related biomarker for ischemic stroke (IS) . When investigating this connection:

Expression Pattern in IS:

• NDUFA11 expression is significantly downregulated in IS patients and models

• Blood expression levels in IS patients: approximately 20.9% compared to normal controls

• Expression is reduced in both in vitro (OGD/R) and in vivo (MCAO) models

Protein Complex Formation:

• The NDUFS1-NDUFA11 protein complex is significantly decreased in IS models

• This suggests IS may damage respiratory chain protein complex I in neuronal mitochondria

Experimental Approaches:

• In vitro models: Oxygen-glucose deprivation/reoxygenation (OGD/R) in neuronal cells

• In vivo models: Middle cerebral artery occlusion (MCAO) in mice

• Human samples: Blood samples from IS patients versus controls

• Detection methods: Western blot, RT-PCR, Co-IP, immunofluorescence (IF)

Therapeutic Potential:

• Network pharmacological analysis suggests metformin hydrochloride as a potential target drug for NDUFA11

What are the impacts of NDUFA11 mutations on mitochondrial function, and how can these be accurately assessed?

NDUFA11 mutations are associated with severe mitochondrial Complex I deficiency . To study these effects:

Functional Impacts:

• Defects in cellular respiratory chain

• Impaired mitochondrial bioenergetics

• Compromised Complex I assembly

• Neurodegenerative phenotypes resembling Leigh's syndrome

Assessment Methods:

• Oxygen Consumption: Measure complex I-dependent oxygen consumption rate (OCR)

  • In control conditions versus with NDUFA11 mutations

  • Add rotenone to inhibit complex I

  • Assess bypass through complex III using duroquinol

• Blue Native PAGE: Analyze complex I assembly state

  • Look for characteristic subcomplexes of 550 kDa and 815 kDa

  • Compare with intact complex I (~980 kDa)

• Mitochondrial Morphology: Assess via microscopy

  • Control cells typically show intact mitochondrial network

  • NDUFA11-deficient cells often exhibit fragmented mitochondria

How can NDUFA11 be utilized in the investigation of disulfidptosis, and what experimental approaches provide the most reliable data?

Disulfidptosis is a novel programmed cell death mechanism involving abnormal accumulation of cytotoxic disulfides. NDUFA11 has emerged as a key disulfidptosis-related biomarker, particularly in ischemic stroke :

Research Strategy for Disulfidptosis Studies:

• Identification of Disulfidptosis-Related Biomarkers (DRBs):

  • Analyze differential gene expression datasets (e.g., GSE16561 for IS)

  • Screen for DE-DRBs between normal and pathological conditions

  • Validate findings with independent datasets (e.g., GSE58294)

• Machine Learning Model Development:

  • Support Vector Machine (SVM) models have shown optimal performance for predicting IS based on disulfidptosis biomarkers

  • Construct calibration curves and decision curve analyses to assess model accuracy

• Protein-Protein Interaction Analysis:

  • Investigate interactions between NDUFA11 and other proteins like NDUFS1

  • Use Co-IP assays to quantify changes in protein complex formation

  • Current research shows the NDUFS1-NDUFA11 protein complex decreases significantly in IS models

• Methodological Controls:

  • Compare with other cell death mechanisms (ferroptosis, apoptosis, necroptosis, autophagy)

  • Use appropriate inhibitors to distinguish disulfidptosis from other death mechanisms

  • Include positive controls for disulfide stress

What are the challenges in resolving contradictory data on NDUFA11's role in respirasome assembly and stability?

Researchers may encounter conflicting data regarding NDUFA11's role in respirasome formation. To address these contradictions:

Observed Discrepancies:

• Some studies report NDUFA11 knockdown disrupts respirasome assembly and reduces activities of complexes I, III, and IV

• Other research focuses primarily on its role in complex I assembly without significant effects on other complexes

Methodological Factors Contributing to Discrepancies:

Experimental Approach to Resolve Contradictions:

• Compare the effects of transient siRNA knockdown versus stable genetic knockout

• Investigate compensatory mechanisms that may activate over time

• Examine NDUFA11 interactions with other complex I subunits using proximity labeling approaches

• Assess respirasome assembly using different detergent conditions for solubilization

How do post-translational modifications of NDUFA11 affect its function, and what are the best methods to study these modifications?

While the search results don't specifically address post-translational modifications (PTMs) of NDUFA11, this represents an important advanced research question:

Predicted PTM Sites and Their Significance:

• The hydrophobic domain likely contains sites for lipid modifications

• The C-terminal hydrophilic domain may contain phosphorylation or acetylation sites

• PTMs could regulate NDUFA11's role in complex I assembly and stability

Recommended Methodology for PTM Analysis:

• Mass Spectrometry Approaches:

  • Use SILAC (Stable Isotope Labeling with Amino acids in Cell culture) to quantify changes in PTMs under different conditions

  • Apply targeted MS/MS analysis to identify specific modifications

  • Consider both bottom-up (peptide) and top-down (intact protein) approaches

• Site-Directed Mutagenesis:

  • Generate recombinant mouse NDUFA11 with mutations at predicted PTM sites

  • Assess effects on:

    • Complex I assembly (BN-PAGE)

    • Protein-protein interactions (Co-IP)

    • Respirasome formation

    • Mitochondrial function (OCR, ATP production)

• PTM-Specific Antibodies:

  • Develop antibodies against predicted modified forms of NDUFA11

  • Use for Western blot and immunoprecipitation studies

  • Apply in different physiological and stress conditions

• Temporal Dynamics:

  • Study PTM changes during complex I assembly process

  • Investigate modifications in response to mitochondrial stress

What emerging technologies might advance our understanding of NDUFA11's role in mitochondrial biology?

Several cutting-edge approaches show promise for deeper investigation of NDUFA11:

Cryo-Electron Microscopy:

• High-resolution structural analysis of NDUFA11 within intact complex I

• Visualization of conformational changes during assembly process

• Study of protein-protein interactions at the atomic level

Genome Editing with CRISPR-Cas9:

• Generation of precise mouse models with NDUFA11 mutations or tagged variants

• Creation of conditional knockout models to study tissue-specific effects

• Introduction of patient-specific mutations to study pathological mechanisms

Single-Cell Omics:

• Analysis of cell-to-cell variability in NDUFA11 expression and function

• Correlation with mitochondrial heterogeneity

• Assessment of compensatory mechanisms in individual cells

Mitochondrial-Targeted Biosensors:

• Real-time monitoring of complex I activity in living cells

• Detection of ROS production associated with NDUFA11 dysfunction

• Visualization of membrane potential changes in response to NDUFA11 manipulation

How might therapeutic strategies targeting NDUFA11 be developed for mitochondrial disorders and ischemic stroke?

Based on current research, several therapeutic approaches warrant investigation:

Potential Therapeutic Strategies:

• Small Molecule Modulators:

  • Development of compounds stabilizing NDUFA11-containing subcomplexes

  • Screening of molecules that enhance complex I assembly in the presence of mutant NDUFA11

  • Investigation of metformin hydrochloride, which has been identified as a potential target drug for NDUFA11 in ischemic stroke

• Gene Therapy Approaches:

  • AAV-mediated delivery of functional NDUFA11 to affected tissues

  • CRISPR-based correction of NDUFA11 mutations

  • RNA therapeutics to modulate NDUFA11 expression

• Mitochondrial Transplantation:

  • Delivery of healthy mitochondria to tissues affected by NDUFA11 deficiency

  • Assessment of complex I assembly rescue

• Disulfidptosis Pathway Modulation:

  • Development of agents preventing NDUFS1-NDUFA11 protein complex disruption

  • Targeting mechanisms of disulfide stress in ischemic conditions

  • Protection of respiratory chain protein complex I from IS-induced damage

Research Priorities:

• Establish appropriate animal models of NDUFA11 deficiency

• Determine tissue-specific requirements for NDUFA11 function

• Identify biomarkers for monitoring therapeutic efficacy

• Develop high-throughput screening platforms for drug discovery