The PSD-95/SAP 90 family of proteins, which are known to bind to and cluster various membrane proteins, are involved in the organization of synaptic structure. These proteins are physically and functionally linked to cytoskeletal and/or signaling proteins. CRIPT (for cysteine-rich interactor of PDZ three), a novel postsynaptic protein, binds specifically to the PDZ3 domain of PSD-95/SAP 90. CRIPT induces the recruitment of PSD-95/SAP 90 to microtubules, and it has been shown to bind directly to microtubules, indicating that it may be responsible for cytoskeletal anchoring of PSD-95/SAP 90. CRIPT is widely expressed outside of the brain and is highly conserved from animals to plants suggesting a wider role in regulating cytoskeleton-membrane associations.