ADF4 Antibody

ADF4 Overview

ADF4 belongs to the Actin-Depolymerizing Factor (ADF) family, which regulates actin filament turnover by severing and depolymerizing filaments. In Arabidopsis, ADF4 is phosphorylated at serine-6 (S6), a modification critical for its cytoskeletal localization and immune function . Key characteristics include:

• Molecular Weight: ~15–17 kDa

• Domains: Single actin-binding domain with phosphorylation-dependent activity .

• Expression: Induced during pathogen infection .

Role in Plant Immunity

ADF4 is essential for activating resistance (R-gene) signaling and pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) . Key findings include:

Immune Signaling Mechanisms

• Gene-for-Gene Resistance: ADF4 is required for RPS5-mediated resistance against Pseudomonas syringae expressing AvrPphB .

• MAPK Signaling: Loss of ADF4 reduces mitogen-activated protein kinase (MAPK) activation, impairing defense responses .

• Actin Cytoskeleton Dynamics: ADF4 phosphorylation regulates actin filament reorganization, enabling immune signal transduction .

Phosphorylation and Localization

• S6 Phosphorylation: Mediated by calcium-dependent protein kinase CPK3, this modification reduces ADF4’s actin-binding capacity, redirecting it to the nucleus .

• Subcellular Dynamics:

  • Non-phosphorylated ADF4 (S6A): Co-localizes with actin filaments.

  • Phosphorylated ADF4 (S6D): Dissociates from actin, enabling nuclear signaling .

Experimental Data and Antibody Applications

Antibodies against ADF4 are used to detect its expression, phosphorylation status, and subcellular localization. Below are key experimental results:

Table 1: ADF4 Functional Studies

Regulatory Mechanisms

ADF4 integrates cytoskeletal dynamics and transcriptional control:

• Actin Binding: Non-phosphorylated ADF4 stabilizes actin networks for immune signaling.

• Nuclear Signaling: Phosphorylated ADF4 facilitates R-gene transcription (e.g., RPS5) and MAPK activation .

Implications for Agricultural Biotechnology

Manipulating ADF4 activity could enhance crop resistance. For example:

• Phosphorylation Mimics: Overexpression of ADF4_S6D variants may decouple cytoskeletal and nuclear roles.

• CRISPR Editing: Targeting ADF4 phosphorylation sites could fine-tune immune responses .

Limitations and Future Directions

• Antibody Specificity: Existing antibodies may not distinguish phosphorylation states without additional validation.

• Translational Gaps: ADF4’s role in non-model plants remains unexplored.