FIGURE 1.

The phosphatidylinositol pathway as known from human studies. Solid arrows indicate kinase action; dashed indicate phosphatase action. Arrows are labelled with the kinases/phosphatases responsible for the reaction, question marks show where there are ambiguities surrounding the reaction, and the proteins are surrounded with a bubble coloured to indicate protein grouping from the key. The seven PIPs are indicated in bold and the structure of the lipids including the location and number of phosphates are shown. The absence of INPP5A is due to evidence suggesting no lipid phosphatase action (Pathway specifics derived from Dickson and Hille, 2019; Nakada-Tsukui et al., 2019).