Essential receptor for extracellular ATP (PubMed:24436418, PubMed:25301072). Binds ATP with high affinity through its extracellular legume-lectin like region (PubMed:24436418). Is required for ATP-induced intracellular calcium response, mitogen-activated protein kinase 3 (MPK3) and MPK6 activation and ATP-induced gene expression (PubMed:24436418, PubMed:25301072). May play a variety of roles in stress resistance (PubMed:24436418). May be involved in protein-protein interactions with RGD motif-containing proteins as potential ligands (PubMed:21483488, PubMed:16361528). Plays probably a structural and signaling role at the plant cell surfaces (PubMed:24436418, PubMed:21483488). Involved in resistance response to the pathogenic oomycetes Phytophthora infestans and Phytophthora capsici. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with RGD motif-containing proteins, suspected to disrupt plasma membrane-cell wall adhesions, via its lectin region. Expressed in leaf petioles. By infection with an avirulent isolate of Phytophthora brassicae. The legume-lectin like region mediates RGD motif recognition. No visible phenotype under normal growth conditions, but mutant plants (e.g. lecrk-I.9-1 and lecrk-I.9-2) are defective in extracellular ATP-induced calcium response and susceptible to an avirulent isolate of the oomycetes Phytophthora brassicae and Phytophthora capsici. Impaired increase of cytoplasmic calcium concentration in response to extracellular ATP (PubMed:25301072). Confers enhanced resistance to late blight mediated by the pathogenic oomycetes Phytophthora infestans and Phytophthora capsici when transfected into Solanum tuberosum and Nicotiana benthamiana. This resistance is associated with a high induction of protease inhibitor genes. Plants over-expressing LECRK19 have more compact rosettes with smaller and slightly wrinkled leaves, reduced height, accumulate anthocyanin and lignin and show enhanced resistance to the oomycete Phytophthora brassicae (PubMed:21483488). Ectopic expression of LECRK19 increases plant response to physical wounding (PubMed:24436418). In the C-terminal section; belongs to the protein kinase superfamily. Ser/Thr protein kinase family. In the N-terminal section; belongs to the leguminous lectin family.