DEF8 (Differentially Expressed in FDCP 8), also known as MAPK8IP3 or JIP3. is a scaffolding protein involved in regulating intracellular signaling pathways, particularly the c-Jun N-terminal kinase (JNK) and mitogen-activated protein kinase (MAPK) cascades. It was initially identified through its differential expression in hematopoietic cells. DEF8 contains multiple protein interaction domains, including a SH3-binding motif and coiled-coil regions, enabling it to assemble signaling complexes that modulate stress responses, apoptosis, and neuronal development.
Antibodies targeting DEF8 are essential tools for studying its role in vesicular transport, autophagy, and lysosomal positioning, as DEF8 interacts with components like kinesin motors and adaptor proteins. Research links DEF8 dysfunction to neurodegenerative disorders (e.g., ALS), cancer metastasis, and immune regulation anomalies. DEF8 antibodies are widely used in techniques such as Western blotting, immunofluorescence, and co-immunoprecipitation to assess protein expression, localization, and molecular interactions. Commercial DEF8 antibodies are typically validated for specificity against human, mouse, or rat homologs, aiding mechanistic studies across disease models. Despite its diverse roles, DEF8's regulatory mechanisms remain under investigation, emphasizing the continued need for reliable antibodies in ongoing research.