A family of ubiquitin-like proteins binds the ATPase domain of Hsp70-like Stch.

The present invention relates to the discovery of a domain on chaperone proteins that binds to ubiquitin-like proteins, including a novel protein Chap1/DSK2 (Ubiquilin-2). Novel biological tools, prophylactics, therapeutics, diagnostics, and methods of use of the foregoing are also disclosed.