BZIP60 Antibody

Target Protein Characteristics

bZIP60 is an ER membrane-bound transcription factor activated through proteolytic processing or mRNA splicing during ER stress. It contains:

• N-terminal bZIP domain (DNA-binding region)

• Transmembrane domain (anchors to ER membrane)

• C-terminal regulatory region (cleaved during activation)

Under stress (e.g., tunicamycin, DTT), bZIP60 is processed to release its N-terminal fragment, which translocates to the nucleus to upregulate ER chaperones like BiP and PDI .

Antibody Applications in Key Studies

The BZIP60 antibody has been pivotal in characterizing protein dynamics and localization:

Mechanistic Insights Revealed by Antibody-Based Assays

• Proteolytic vs. Splicing Activation:
  Initial studies suggested proteolytic cleavage , but subsequent work showed IRE1-mediated mRNA splicing removes a 23-bp intron, producing a truncated protein (bZIP60s) . Antibodies distinguished between the full-length (bZIP60u, 295 aa) and spliced (bZIP60s, 258 aa) forms .

• Subcellular Localization:
  Immunofluorescence confirmed ER retention of unprocessed bZIP60 and nuclear translocation of the spliced form under stress .

Role in Plant Immunity

The antibody helped elucidate bZIP60’s immune functions:

• Pathogen Defense:

  • Nicotiana benthamiana with silenced bZIP60 showed increased susceptibility to Pseudomonas cichorii .

  • Arabidopsis bzip60 mutants exhibited compromised resistance to Botrytis cinerea and Drechslera gigantea .

• Signaling Crosstalk:
  bZIP60 cooperates with salicylic acid (SA) pathways to enhance systemic acquired resistance (SAR), as shown by reduced PR1 expression in ire1a/ire1b and bzip60 mutants .

Technical Validation

• Specificity: Polyclonal antibodies against the N-terminal bZIP domain reliably detect both isoforms without cross-reactivity to related proteins like bZIP28 .

• Quantitative Use: CE-LIF and qRT-PCR correlated antibody-detected protein levels with spliced mRNA abundance during viral (TuMV) infection .

Research Limitations and Solutions

• Low Spliced Isoform Detection: Spliced bZIP60 mRNA forms stable secondary structures, reducing reverse transcription efficiency. Optimized primers and antibody combinations resolved this .

• Functional Redundancy: bZIP60 partially overlaps with bZIP28; dual mutants (bzip28/bzip60) are required for phenotypic analysis .