To investigate the curative effects of oral and nasal administration of chicken type II collagen (CII) on adjuvant arthritis (AA) in rats with meloxicam-induced intestinal lesions.

To investigate the effects and mechanisms of melatonin on immunological liver injury in mice.

Endoplasmic reticulum-associated degradation (ERAD)is a protein quality control mechanism that eliminates unwanted proteins from the endoplasmic reticulum (ER) through a ubiquitin-dependent proteasomal degradation pathway. gp78 is a previously described ER membrane-anchored ubiquitin ligase (E3) involved in ubiquitination of ER proteins. AAA ATPase (ATPase associated with various cellular activities) p97/valosincontaining protein (VCP) subsequently dislodges the ubiquitinated proteins from the ER and chaperones them to the cytosol, where they undergo proteasomal degradation. We now report that gp78 physically interacts with p97/VCP and enhances p97/VCP-polyubiquitin association. The enhanced association correlates with decreases in ER stress-induced accumulation of olyubiquitinated proteins. This effect is abolished when the p97/VCP-interacting domain of gp78 is removed. Further, using ERAD substrate CD3, gp78 consistently enhances p97/VCP-CD3 binding and facilitates CD3 degradation. Moreover, inhibition of endogenous gp78 expression by RNA interference markedly increases the levels of total polyubiquitinated proteins, including CD3, and abrogates VCP-CD3 interactions. The gp78 mutant with deletion of its p97/VCP-interacting domain fails to increase CD3 degradation and leads to accumulation of polyubiquitinated CD3, suggesting a failure in delivering ubiquitinated CD3 for degradation. These data suggest that gp78-p97/VCP interaction may represent one way of coupling ubiquitination with retrotranslocation and degradation of ERAD substrates.