SPAK Antibody / STK39

Overview

SPAK Antibody / STK39 is an antibody targeting STK39, raised in Rabbit for protein detection and localization studies where these specifications are required.

Key elements and design rationale

• Target: STK39 (reported localization: Nuclear, cytoplasmic).
• Antibody identity: Polyclonal (rabbit origin); Rabbit Ig.
• Conjugate/label: Unconjugated (affects detection chemistry and multiplex compatibility).
• Format: Purified.
• Species reactivity: Human.
• Listed applications: WB, IHC-P (refer to on-page specifications for application-specific guidance).

Biological background

SPAK is a serine/threonine kinase containing an N-terminal series of proline and alanine repeats (PAPA box), followed by a serine/threonine kinase catalytic domain, a nuclear localization signal, a consensus caspase cleavage recognition motif, and a C-terminal region. Northern blot analysis detects ubiquitous expression, most abundantly in brain and pancreas. SPAK can phosphorylate itself and an exogenous substrate in vitro. SPAK immunoprecipitates from transfected mammalian cells in a complex with another serine/threonine kinase that phosphorylates catalytically inactive SPAK. SPAK activates the p38 MAP kinase pathway in cotransfection assays. Full-length SPAK is expressed in the cytoplasm in transfected cells, while a mutant corresponding to caspase-cleaved STK39 localizes predominantly in the nucleus.

Research relevance and current trends

• Comparative expression profiling across cell types, tissues, or perturbations (e.g., drug treatment, genetic editing, or differentiation).
• Subcellular localization and trafficking studies, including co-localization with pathway markers in microscopy-based assays.
• Integration of protein-level measurements with transcriptomics or proteomics to relate abundance to regulation and phenotype.

Common research applications

• Western blotting: researchers commonly compare relative signal levels across conditions and use appropriate negative/positive controls for interpretation.
• Immunohistochemistry: researchers commonly compare relative signal levels across conditions and use appropriate negative/positive controls for interpretation.

Interpretation should account for antibody-dependent factors such as epitope accessibility, isoforms, and sample preparation differences across workflows.

Notes for experimental interpretation

• Isoforms and PTMs: many targets have multiple isoforms and post-translational modifications that can shift apparent signal or localization; interpret bands/signals accordingly.
• Epitope context: binding can depend on protein conformation and sample processing; region information in the title/immunogen can help anticipate what may be detected.
• Species differences: predicted or validated reactivity may vary by ortholog sequence and sample context; confirm in your model system.
• Control concepts: include negative controls (no-primary/isotype), and where possible genetic controls (KO/KD) or independent antibodies to strengthen conclusions.

Customization & Add-ons: Can’t find the antibody you need—or require a custom format for your assay? We can help you source the best match or support custom antibody solutions for diverse research needs, including species and isotype selection, conjugations and labeling (e.g., HRP/AP, biotin, fluorophores), purification grade options (Protein A/G, affinity purified), formulation preferences (buffer selection, carrier-free, glycerol-free), custom concentrations and aliquoting, low-endotoxin options for cell-based work, and application-focused QC/validation support (project dependent). Click Talk to a Scientist to submit a request, email us at support@biohippo.com, or explore our Research Services for additional support—our team will follow up with feasibility details and next steps.