Transcriptional activator that specifically binds DNA sequence 5'-AGAAnnTTCT-3' known as heat shock promoter elements (HSE). Seems to be involved in other environmental stress responses. Activates ascorbate peroxidase 2 (APX2) in addition to several heat shock protein (HSPs). Binds to the promoter of SGIP1 and activates its expression in heat acclimated plants (PubMed:30778176). Involved in the mechanisms necessary for quick response to heat and subsequent heritable transgenerational memory of heat acclimation (global warming) such as early flowering and attenuated immunity; this process includes epigenetic regulation as well as post-transcriptional gene silencing (PTGS) (PubMed:30778176). In response to heat, HSFA2 is activated and promotes the expression of REF6 which in turn derepresses HSFA2, thus establishing an heritable feedback loop able to trigger SGIP1 and subsequent SGIP1-mediated SGS3 degradation; this prevents the biosynthesis of trans-acting siRNA (tasiRNA) and leads to the release of HTT5, which drives early flowering but attenuates immunity (PubMed:30778176). Homotrimer (By similarity). Interacts with SUMO1 (PubMed:20521085). Binds to HSBP (PubMed:20388662). A number of isoforms are produced. According to EST sequences. By high light and hydrogen peroxide (H(2)O(2)) (PubMed:16649111, PubMed:17059409, PubMed:17085506, PubMed:30778176). Up-regulated by heat stress (at 30 degrees Celsius) and remains up-regulated transgenerationally in the unstressed progeny (at 22 degrees Celsius) via heat-induced REF6-dependent depletion of H3K27me3 marks within its coding regions (PubMed:16649111, PubMed:17059409, PubMed:17085506, PubMed:30778176). The hydrophobic-rich region (HR-A/B) corresponds to the oligomerization domain. AHA motifs are transcriptional activator elements. Exhibits temperature-dependent phosphorylation. Sumoylated at Lys-315. Sumoylation represses its function. Heat-sensitive phenotype (PubMed:20521085). Reduced expression of SGIP1 (PubMed:30778176). Plants overexpressing HSFA2 show increased tolerance to combined environmental stresses. Belongs to the HSF family. Class A subfamily.