Syndecans (SDCs) are a major class of cell surface heparan sulphate proteoglycans (HSPGs) and the member syndecan-2 (SDC2) plays a critical role in EPHB-mediated spine formation in hippocampal neurons. Ethell et al. suggest that one of the mechanisms by which EPHB receptors regulate spine morphology is through phosphorylation of SDC2 (Ethell et al. 2001, Ethell & Yamaguchi 1999). Activated EPHB2 phosphorylates SDC2 at tyrosine residues Y189 and Y201 (Y179 and Y191 according to uniprot reference sequence) in the C1 and V regions respectively (Ethell et al. 2001).