Involved in pollen tube guidance into micropyle. Participates in perception of the ovule-secreted peptide signal LURE1. Interacts with PRK6. In pollen tubes, mainly located in the plasma membrane to the tip region. Expressed in mature pollen and in germinating pollen tubes. Palmitoylated. No visible phenotype. Lip1 and lip2 double mutants have a reduced male transmission. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.