Ubiquilins in the crosstalk among proteolytic pathways.

Protein degradation occurs through several distinct proteolytic pathways for membrane and cytosolic proteins. There is evidence that these processes are linked and that crosstalk among these major protein degradation pathways occurs. Ubiquilins, a family of ubiquitin-binding proteins, are involved in all protein degradation pathways. This minireview provides an overview of ubiquilin function in protein degradation and contrasts it with sequestosome-1 (p62), a protein that also has been implicated in multiple proteolytic pathways.