HOP3 a new regulator of the ER stress response in Arabidopsis with possible implications in plant development and response to biotic and abiotic stresses.

HOPs (heat shock protein 70 (HSP70)-heat shock protein 90 (HSP90) organizing proteins) are a highly conserved family of cytosolic cochaperones. In a recent study we showed that HOP3, a member of the HOP family in Arabidopsis, plays an essential role during endoplasmic reticulum (ER) stress in plants. Interestingly, we also demonstrated that AtHOP3 interacts with binding immunoglobulin protein (BiP), a major ER-resident chaperone. All these data suggest that HOP3 could assist BiP in protein folding in the ER. These findings open the exciting possibility that HOP3, through its role in the alleviation of ER stress, could play an important function during different developmental processes and in response to different biotic and abiotic stresses.