Involved in resistance to abiotic stress. Homodimer and heterodimers (PubMed:29272523). Interacts with CYSTM3, CYSTM4, CYSTM5, CYSTM6, CYSTM10, WIH1/CYSTM13 and CYSTM11 (PubMed:29272523). Binds weakly to CYSTM1, CYSTM2 and CYSTM12 (PubMed:29272523). Mostly expressed in siliques and, to a lower extent, in stems, roots, leaves and flowers. Induced by salt, heat and drought. Belongs to the CYSTM1 family.