The 198-amino acid rat Csp protein contains an N-terminal J domain, followed by a cysteine string and a C-terminal domain. They noted that most of the cysteines are palmitoylated and are required for membrane targeting of Csp. ratCSP binding sites for G proteins, one that overlaps the J domain and binds G-alpha subunits, and another between the J domain and cysteine string that binds G-beta (see GNB1) and/or the G-alpha-beta-gamma trimer.

The complex functioned as an ATP-dependent chaperone that reactivated a denatured substrate. Sgt overexpression in cultured rat hippocampal neurons inhibited neurotransmitter release, suggesting that the Csp/Sgt/Hsc70 complex is important for maintenance of a normal synapse.