FTSH8 Antibody

Definition and Target Specificity

The FTSH8 antibody primarily recognizes the FTSH8 protein (Arabidopsis thaliana UniProt: O80860), a subunit of the chloroplast FTSH protease complex . Due to 92% sequence homology between FTSH8 and FTSH2 (VAR2), this antibody cross-reacts with both isoforms, making it unsuitable for distinguishing between them without additional controls .

Subunit Composition

• The FTSH complex in Arabidopsis contains four "type B" subunits (FTSH2/FTSH8) and two "type A" subunits (FTSH1/FTSH5) .

• Stoichiometric analysis via mass spectrometry revealed a 2:1 ratio of type B to type A subunits .

Functional Roles

• D1 Protein Repair: Facilitates degradation of damaged D1 subunits in Photosystem II under high-light stress .

• Thylakoid Biogenesis: Essential for chloroplast membrane development; mutants exhibit variegated phenotypes .

Western Blot Validation

• Detects FTSH8/FTSH2 in plant extracts (e.g., Arabidopsis, spinach) .

• Example: A 65.6 kDa band in Nicotiana tabacum lysates confirms antibody specificity .

Cross-Species Compatibility

• Predicted reactivity across angiosperms, but absent in algae (Chlamydomonas) .

Limitations and Considerations

• Cross-Reactivity: Cannot differentiate FTSH8 from FTSH2 without gene-edited controls (e.g., var2 mutants) .

• Storage: Lyophilized antibodies require aliquoting to prevent freeze-thaw degradation .

Recent Advancements

A 2024 study demonstrated FTSH8's role in stabilizing Photosystem II core complexes, with knockout mutants showing impaired photoprotection . Mass spectrometry further validated its interaction with Psb28, a Photosystem II assembly factor .