The residues upstream of this domain are the probablepalmitoylation sites, particularly two cysteines. The domain hasa putative PEST site at the very start that seems to beresponsible for poly-ubiquitination [1]. PEST domains arepolypeptide sequences enriched in proline (P), glutamic acid(E), serine (S) and threonine (T) that target proteins for rapiddestruction. The whole domain, in conjunction with a C-terminaldomain of the longer protein, is necessary for dimerisation ofthe whole protein [2]. Polyubiquitination (PEST) N-terminal domain of MAGUK MAGUK_N_PEST