Central component of stress responses that interacts with poly(A)-binding proteins. Negative regulator of abscisic acid (ABA) responses, including resistance to drought and freezing as well as stomatal closure regulation. Mediates resistance to the bacterial necrotroph pathogen Erwinia carotovora subsp. carotovora and promotes the induction of marker genes for systemic acquired resistance (SAR). Interacts with PAB2, PAB4 and PAB8. Interacts with MPC. Expressed in cauline leaves, stems, rosette leaves, immature siliques and primary inflorescences. Strongly induced by abiotic stresses such as abscisic acid (ABA), salicylic acid (SA), wounding, high light, cold stress, oxidative stress, hypergravity and dehydration. Accumulates upon root colonization by the plant-growth-promoting rhizobacterium (PGPR) Paenibacillus polymyxa. Slightly reduced levels in response to UV-A illumination, salt stress and heat shock treatment. Contains a PAM2-like motif, which seems to be involved in the binding to the PABC/CTC domain of PAB proteins. Hypersensitive to abscisic acid (ABA) leading to improved tolerance to both drought and freezing, as well as impaired seed germination in the presence of ABA.