PCP4 (Purkinje Cell Protein 4), also known as PEP-19. is a small, intrinsically disordered protein predominantly expressed in the brain, particularly in cerebellar Purkinje cells and specific neuronal populations. It plays roles in calcium signaling, apoptosis regulation, and modulating interactions with calmodulin and other calcium-sensing proteins. PCP4's structure includes two EF-hand motifs, though only one binds calcium, influencing its functional dynamics. Dysregulation of PCP4 has been implicated in neurological disorders, including Alzheimer’s disease, Huntington’s disease, and spinocerebellar ataxia, as well as cancers like medulloblastoma and leukemia.
PCP4 antibodies are essential tools for studying its expression, localization, and molecular interactions. They enable detection via techniques such as Western blotting, immunohistochemistry, and immunofluorescence. Research using these antibodies has revealed PCP4's involvement in neurodevelopment, synaptic plasticity, and tumor progression. For instance, reduced PCP4 levels correlate with cognitive decline in Alzheimer’s models, while its overexpression in cancers like breast adenocarcinoma suggests potential oncogenic roles. Recent studies also highlight PCP4's diagnostic potential as a biomarker for certain cancers or neurodegenerative conditions. However, challenges remain in standardizing antibody specificity due to PCP4's low molecular weight and disordered structure. Ongoing work aims to clarify its precise mechanisms and therapeutic relevance.