AtITPK4- Arabidopsis thaliana ITPK4 (PDB entry 7PUP), EhITPK1- Entamoeba histolytica ITPK1 (PDB entry 1Z2P), HsITPK1- Homo sapiens ITPK1 (PDB entry 2QB5), ZmITPK1- Zea mays ITPK1 (PDB entry 7ZN5), AtITPK1- Arabidopsis thaliana ITPK1 (Alphafold Protein Structure Database entry Q9SBA5). Residue single letter codes shown in lower case for residues unresolved in structures of AtITPK4 and ZmITPK1. Note that the alignment of the unresolved residues in ZmITPK1 follows that predicted by the corresponding Alphafold model. Residues with at least 80% homology are shown with black backgrounds, while those conserved by residue class in at least four of the five sequences are shown with light grey backgrounds. Secondary structural elements of AtITPK4 are indicated by red cylinders (α-helices) or by blue boxes (β-strands) and labelled. The regions of the tab and tether insertions are enclosed in magenta and blue boxes, respectively. Residues forming the unique active site ion pair in AtITPK4 are indicated by asterisks (*).