Pollen tube attractants guiding pollen tubes to the ovular micropyle (PubMed:23271953, PubMed:29109411). Attracts specifically pollen tubes from A.thaliana, but not those from A.lyrata (PubMed:23271953). Triggers endocytosis of MDIS1 in the pollen tube tip (PubMed:26863186). Interacts with MDIS1, MIK1, MIK2 and TDR/PXY, but not with MDIS2 (PubMed:26863186). Binds to PRK6 LRRs (PubMed:29109411). found at the micropylar end of the female gametophyte, possibly at the filiform apparatus of the synergid cell. Difuses to the surface of the funiculus of the ovule through the micropyle. Expressed in the pistil. Detected exclusively in the synergid cells. Belongs to the DEFL family. Lacks 1 of the 4 disulfide bonds, which are conserved features of the family.