sur-6 Antibody

Definition and Molecular Characterization of SUR-6 Antibody

The SUR-6 antibody is a polyclonal serum developed to detect the SUR-6 protein, a regulatory subunit of protein phosphatase 2A (PP2A) in Caenorhabditis elegans (C. elegans). SUR-6 (also known as PR55/B55) belongs to the B55 family of PP2A regulatory subunits, which modulate PP2A’s phosphatase activity to regulate critical cellular processes, including centriole duplication, mitotic spindle assembly, and Ras/Raf/MEK/ERK signaling .

Key Molecular Features:

• Structure: SUR-6 forms a heterotrimeric complex with the PP2A catalytic subunit (LET-92) and a scaffolding subunit .

• Function: Facilitates PP2A’s role in dephosphorylating substrates involved in cell cycle progression and signal transduction.

• Epitope Recognition: Polyclonal anti-SUR-6 sera target cytoplasmic and centrosomal SUR-6, validated via immunoblotting and immunoprecipitation .

Role in Centriole Duplication

SUR-6 is essential for centriole duplication in C. elegans. RNA interference (RNAi) of sur-6 resulted in:

• Monopolar spindles (24% of embryos)

• Asymmetric spindles (47.5% of embryos)

• Partial rescue of centriole duplication defects in zyg-1(it25) mutants at semipermissive temperatures .

Table 1: SUR-6 Antibody Applications

Regulation of Ras Signaling

SUR-6 promotes Ras signaling by enhancing Raf kinase activity:

• sur-6(sv30) mutants exhibited 5-fold reduced ERK phosphorylation compared to wild-type .

• Epistasis analysis placed SUR-6 upstream of Raf but downstream of Ras in the signaling cascade .

Cross-Reactivity and Specificity

The SUR-6 antibody demonstrates high specificity:

• Detects a single band of ~50 kDa in C. elegans lysates .

• No cross-reactivity with other PP2A regulatory subunits (e.g., SUR-2, SUR-4) .

• Validation via RNAi knockdown confirmed reduced SUR-6 signal in embryos .

Comparative Insights from Related Antibody Systems

While SUR-6 itself is not a therapeutic target, studies on analogous antibody systems highlight principles relevant to its functional analysis:

• SARS-CoV-2 Neutralizing Antibodies: Techniques like bead-based immunoassays and pseudovirus neutralization assays parallel methods used to study SUR-6’s role in PP2A complexes.

• Antibody Cocktails: Dual-targeting strategies (e.g., LY-CoV555 + LY-CoV016) mirror combinatorial approaches to dissect SUR-6’s interaction networks.

Potential Research Applications:

1. Cell Cycle Regulation: Investigate SUR-6’s role in checkpoint control and centrosome dynamics.

2. Developmental Biology: Study SUR-6’s impact on Ras-dependent morphogenesis.

3. Disease Models: Explore SUR-6 dysregulation in cancers linked to PP2A or Ras pathway mutations.

Table 2: Key Studies on SUR-6 Antibody