C. elegans body draft 2

Different partitioning genes (encoding Par proteins) allowed the zygote to part into two poles. Par proteins turned out to be homologous in most eukaryotes (including humans). Loss of posterior PARs lead to expansion of anterior and vice versa. This all suggested a competition of some sort between the different PAR proteins. Kinase domains in the proteins anterior Par kinase domains phosphorylated the lipid binding domains of posterior Par proteins to stop them from accessing the membrane vice versa.