What Is CDH3 (P-cadherin)?

CDH3, commonly referred to as P-cadherin (placental cadherin), is a member of the classical cadherin superfamily of calcium-dependent cell adhesion molecules. Encoded by the CDH3 gene located on human chromosome 16q22.1, CDH3 shares the hallmark cadherin architecture: an extracellular domain comprising five tandem cadherin repeats (EC1–EC5) that mediate homophilic binding in a calcium-dependent manner, a single-pass transmembrane domain, and a cytoplasmic tail that associates with the actin cytoskeleton via catenin complexes.

CDH3 was originally identified in placental tissue and is expressed in a variety of epithelial tissues including skin, breast, and gastrointestinal epithelium. Its extracellular domain facilitates trans-homophilic dimerization between adjacent cells, establishing the tight cell–cell contacts essential for epithelial barrier integrity and tissue morphogenesis. The cytoplasmic tail recruits β-catenin and p120-catenin, thereby linking the adhesion complex to intracellular signaling cascades including the Wnt pathway.

Biological Significance and Disease Associations

CDH3 plays pivotal roles in epithelial development and homeostasis. During embryogenesis, CDH3-mediated adhesion contributes to the organization of stratified epithelia and placental development. Postnatally, CDH3 is expressed in the basal layer of the epidermis, hair follicles, and the retinal pigment epithelium, where it regulates progenitor cell compartmentalization.

Loss-of-function mutations in CDH3 cause two rare autosomal recessive disorders: hypotrichosis with juvenile macular dystrophy (HJMD) and ectodermal dysplasia, ectrodactyly, and macular dystrophy (EEM syndrome), underscoring the protein's indispensable role in skin appendage development and retinal pigment epithelium integrity.

In oncology, CDH3 expression is frequently dysregulated. Unlike the tumor-suppressive E-cadherin (CDH1), CDH3 can be aberrantly overexpressed in breast, colorectal, gastric, bladder, and pancreatic carcinomas, where its elevated levels correlate with increased invasiveness, poor differentiation, and unfavorable prognosis. CDH3 overexpression has been proposed to promote collective cell migration and metastatic dissemination, making it an attractive therapeutic target and a potential biomarker for patient stratification.

Recombinant Human CDH3 Protein: Production and Biochemical Properties

Recombinant Human CDH3 Protein is typically produced using mammalian or insect cell expression systems to ensure proper N-glycosylation and disulfide bond formation, both of which are critical for maintaining the native fold of the cadherin extracellular domain and its calcium-binding competency. The recombinant construct generally encompasses the full-length or partial extracellular domain of CDH3, enabling studies of homophilic binding kinetics, cis-dimerization, and interaction with potential heterophilic binding partners.

Key biochemical features of the recombinant protein include: (1) preserved calcium-binding sites within each EC repeat, with calcium coordination at the interdomain linkers essential for conferring the rigid rod-like conformation; (2) an intact EC1 domain bearing the conserved His-Ala-Val (HAV) motif critical for adhesive specificity; and (3) appropriate glycosylation patterns that influence protein stability, solubility, and receptor recognition in functional assays.

Quality control testing typically includes SDS-PAGE for purity assessment, size-exclusion chromatography or dynamic light scattering for homogeneity, and functional binding assays to confirm biological activity prior to release.

Research Applications of Recombinant Human CDH3 Protein

Recombinant Human CDH3 Protein is a versatile reagent enabling multiple experimental workflows:

• Protein–protein interaction studies: Surface plasmon resonance (SPR), bio-layer interferometry (BLI), and co-immunoprecipitation assays using recombinant CDH3 to characterize homophilic binding affinities and identify novel interaction partners.
• Immunoassay development: Recombinant CDH3 serves as a coating antigen or standard in ELISA formats for measuring soluble CDH3 (shed ectodomain) in serum or conditioned media as a potential cancer biomarker.
• Cell adhesion and migration assays: Substrate-coated recombinant CDH3 extracellular domain is used to study integrin-independent, cadherin-mediated adhesion in epithelial and cancer cell lines, and to evaluate the effect of blocking antibodies or small molecule inhibitors on cell adhesion.
• Antibody validation: Recombinant CDH3 is used as a positive control antigen for validating anti-CDH3 antibodies in Western blot, immunoprecipitation, and flow cytometry applications.
• Drug discovery and therapeutic development: CDH3's overexpression in multiple tumor types makes recombinant CDH3 a key reagent for screening antibody–drug conjugate (ADC) candidates and bispecific antibodies targeting CDH3-positive tumors.

Storage, Handling, and Formulation Recommendations

To maintain the biological activity and structural integrity of Recombinant Human CDH3 Protein, adherence to appropriate storage and handling practices is essential:

• Storage temperature: Aliquot upon receipt and store at –70 °C or below for long-term storage. Avoid repeated freeze–thaw cycles, which can lead to protein aggregation and loss of activity.
• Working aliquots: Short-term storage at 4 °C is acceptable for up to one week if the protein will be used within that period. Keep aliquots on ice during handling.
• Reconstitution: If supplied lyophilized, reconstitute in sterile distilled water or the buffer recommended in the product datasheet. Allow the vial to equilibrate to room temperature before opening. Gently mix; do not vortex.
• Carrier protein: For low-concentration working solutions, supplementing with a carrier protein such as 0.1% BSA is recommended to minimize adsorption to tube surfaces and maintain stability.
• Calcium supplementation: Because CDH3 function is strictly calcium-dependent, ensure that assay buffers contain adequate free Ca²⁺ (typically 1–2 mM) when performing functional experiments.

Always consult the product-specific Certificate of Analysis (CoA) and datasheet for lot-specific formulation details, concentration, and recommended working dilutions.