LACS7 Antibody

Definition and Target Specificity

The LACS7 antibody detects LACS7, a membrane-associated enzyme that activates fatty acids into acyl-CoA esters for peroxisomal β-oxidation. It exhibits cross-reactivity with LACS6 due to structural similarities between these paralogs . Key characteristics include:

Role in β-Oxidation

LACS7 converts fatty acids (e.g., oleate [C18:1]) to acyl-CoA esters, a prerequisite for β-oxidation. Antibody-based assays revealed:

• Substrate specificity: LACS7 has a 3.2-fold higher C18:1-CoA/C8:0-CoA synthetase activity ratio compared to LACS6 .

• Genetic complementation: Expression of LACS7 restores β-oxidation in yeast (pxa1/pxa2/faa2Δ mutants), while LACS7 lacking peroxisomal targeting signals (PTS1/PTS2) fails to rescue .

Interaction with CTS Transporter

Co-immunoprecipitation and sucrose gradient sedimentation using the LACS7 antibody demonstrated:

• Complex formation: LACS7 co-migrates with the peroxisomal ABC transporter CTS in a stable ~700 kDa complex .

• Functional coupling: This interaction facilitates fatty acid transport into peroxisomes, as shown by impaired oleate degradation in cts-1 mutants .

Subcellular Localization

The antibody confirmed dual peroxisomal targeting of LACS7 via:

• PTS1: C-terminal serine-lysine-leucine (SKL) motif .

• PTS2: N-terminal nonapeptide (RQIVLGPAL) .

Protein Complex Analysis

• Identified LACS7 in high-MW complexes (700–1,100 kDa) using blue native-PAGE and anti-LACS6/7 antibodies .

• Demonstrated partial overlap with acyl-CoA oxidase 1 (ACX1) in sucrose gradients, suggesting metabolic channeling .

Mutant Phenotyping

• PTS deletion mutants: Loss of peroxisomal LACS7 activity in LACS7-PTS lines correlated with defective seedling growth under fatty acid-dependent conditions .

Technical Considerations

• Cross-reactivity: Antibody detects both LACS6 and LACS7; use genetic controls (e.g., lacs6 mutants) for specificity .

• Buffer compatibility: Effective in β-dodecylmaltoside and Triton X-100 solubilization buffers .