FTSHI3 Antibody

Target Protein: FTSH Protease 3 (FTSHI3)

FTSHI3 is a mitochondrial inner membrane-bound AAA+ protease involved in the degradation of damaged subunits of Complex I (CI) in the oxidative phosphorylation (OXPHOS) pathway . Unlike canonical FTSH proteases, FTSHI3 lacks proteolytic activity due to mutations in its HEXXH motif . Its primary role involves disassembling the matrix arm domain of CI through ATPase-dependent unfolding, enabling proteolysis by other enzymes .

Key Features of FTSHI3:

• Domain Architecture: Contains an N-terminal "peptidase M41 FtsH extracellular" domain and a C-terminal AAA+ ATPase domain .

• Complex Formation: Forms a distinct 1-MD complex separate from other FTSH proteases, potentially with OTP51, a splicing factor for group II introns .

• Functional Partners: Directly interacts with the PSST subunit of CI to mediate disassembly .

Development and Validation of the FTSHI3 Antibody

Antibodies targeting FTSHI3 have been generated using epitope tags (e.g., HA, GFP) or peptide antigens. Key validation steps include:

Table 1: Antibody Validation Strategies

Research Applications

The FTSHI3 antibody has been pivotal in:

• Protein-Protein Interaction Studies: Demonstrating direct binding between FTSHI3 and the N-terminal domain of PSST via Co-IP assays .

• Turnover Analysis: Tracking CI subunit degradation rates in Arabidopsis mutants (e.g., rmb1 ciaf1) .

• Subcellular Localization: Confirming FTSHI3’s presence in mitochondrial membranes .

Challenges and Limitations

• Low Signal Specificity: HA- and GFP-tagged FTSHI3 showed inconsistent detection, necessitating optimized protocols .

• Cross-Reactivity: Antibodies raised against FTSHI3’s paralogs (e.g., FTSH1/2) may require stringent validation .

Future Directions

• Investigate FTSHI3’s role in other OXPHOS complexes .

• Develop high-affinity monoclonal antibodies to improve detection reliability .