Velis are a family of small synaptic proteins that interact with other proteins at the post-synaptic density (PSD) of neuronal synapses. Velis contain the PDZ motif involved in recruiting cell adhesion molecules, receptors, and channels. Veli1 (also designated Lin-7A and MALS-1), Veli2 (also designated Lin-7B and MALS-2), and Veli3 (also designated Lin-7C and MALS-3) are mammalian homologs of C. elegans LIN-7. Veli proteins are ubiquitously expressed with high expression in brain, liver, and testis. Velis are localized at the synaptic junctions in neurons. Velis bind to CASK, a neurexin-binding protein highly concentrated in synapses, and Mint1, a binding partner with a vesicle trafficking protein.