NUDT16L1, also known Syndesmos, is a cytoplasmic protein that interacts specifically with the cytoplasmic domain of syndecan-4, and it co-localizes with syndecan-4 in focal contacts. This protein interacts with the focal adhesion adaptor protein paxillin. The binding of syndesmos to paxillin is direct, and these interactions are triggered by the activation of protein kinase C.