Cell polarization and subsequent morphogenesis are essential processes common to all living organisms. In fungi and animals, several factors have been shown to provide intracellular polarization cues, whereas such polarity factors are not well conserved in plants. We previously found that Never in mitosis A-related kinase (NEK), mitotic kinase of fungi and animals, regulates growth polarity in land plants. NEK may be co-opted as a polarization factor during plant evolution. To elucidate the mechanism of growth polarity, we used the tip growth of rhizoids in the liverwort Marchantia polymorpha as a model system to identify new polarization factors. MpNEK1 localizes to apical microtubule foci to stabilize growth polarity of rhizoids. To determine its mode of action, we identified about 400 proteins that interact with MpNEK1 using proximity-dependent labelling and co-immunoprecipitation. Among these proteins, we found strong interactors of MpNEK1. We generated their mutants by CRISPR/Cas9, which showed abnormal growth of rhizoids. Some interactors localized to the droplet-like structures in the apical dome of rhizoids. This apical localization was dependent on MpNEK1 and microtubules. These interactors may generate a novel organelle, phytopolarisome, at the apical dome of rhizoids to regulate polarized growth.