Clostridial DivIVA and MinD interact in the absence of MinJ

In B. subtilis, MinD and DivIVA interact through MinJ; here, however, we discovered that the MinD and DivIVA proteins of both C. difficile, and C. beijerinckii, interact directly, which is surprising in the latter case, since that organism also encodes a MinJ homologue. We confirm this interaction using both in vitro and in vivo methods. We also show that C. beijerinckii MinJ is probably not in direct contact with DivIVACb and, unlike B. subtilis MinJ, does not mediate the MinDCb and DivIVACb interaction. Our results suggest that the Clostridia Min system uses a new mechanism of function.