Acts as negative regulator of WRKY33 transcription factor activity in the promotion of defense gene expression. Acts as a negative regulator of pathogen-associated molecular pattern (PAMP)-induced responses to modulate resistance to pathogens. Interacts with MPK3 and MPK6. A number of isoforms are produced. According to EST sequences. Phosphorylated on serine and threonine residues by MPK6 following treatment with the pathogen-associated molecular pattern (PAMP) flg22. MAP kinase-mediated phosphorylation after PAMP elicitation causes degradation of VQ4, allowing WRKY33 to promote transcription from defense genes.