ssr4 Antibody

Definition and Biological Context

SSR4 is encoded by the SSR4 gene (NCBI Gene ID: 6748) and forms part of the heterotetrameric TRAP complex (SSR1, SSR2, SSR3, SSR4). This complex facilitates protein transport across the endoplasmic reticulum membrane and ensures proper glycosylation . The SSR4 antibody (e.g., Proteintech 11655-2-AP) is a polyclonal rabbit IgG antibody that detects human, mouse, and rat SSR4 .

Key Applications in Research

The SSR4 antibody has been utilized in diverse experimental settings:

• Western Blotting (WB): Detects SSR4 at ~19 kDa in human fibroblasts, confirming reduced TRAP complex stability in congenital disorders of glycosylation (CDG) .

• Immunohistochemistry (IHC): Validates SSR4 overexpression in esophageal squamous cell carcinoma (ESCC) and colon adenocarcinoma (COAD) tissues compared to normal samples .

• Immunofluorescence/Immunocytochemistry (IF/ICC): Localizes SSR4 in cellular compartments to study its interaction with the oligosaccharyltransferase complex .

• Functional Rescue Experiments: Overexpression of wild-type SSR4 in mutant fibroblasts partially restores glycosylation, demonstrating its therapeutic potential .

Role in Congenital Disorders of Glycosylation (CDG)

A de novo mutation in SSR4 (c.316delT) was linked to CDG, causing frameshift (p.F106Sfs*53) and destabilizing the TRAP complex. Key findings include:

• Protein Expression: SSR4 was undetectable in patient fibroblasts, while SSR1, SSR2, and SSR3 levels dropped by 50–90% .

• Glycosylation Rescue: Transfecting mutant cells with wild-type SSR4 restored glycosylation of markers like Glyc-ER-GFP by 48% .

Cancer Biomarker Studies

SSR4 overexpression correlates with advanced tumor stages and immune infiltration:

Significance and Future Directions

The SSR4 antibody enables critical insights into:

• Disease Mechanisms: Unraveling TRAP complex dysfunction in CDG and cancer .

• Therapeutic Targets: Identifying SSR4 as a biomarker for immunotherapy in ESCC and COAD .

• Diagnostic Tools: Validating SSR4 overexpression in tissue microarrays for clinical prognostication .