In this direction, Orc2 (one protein included in the origin recognition complex, ORC, implicated in the initiation of DNA replication during S phase) is also located on kinetochores during mitosis in human cells; in agreement with this localization, some observations indicate that Orc2 in yeast is implicated in sister chromatid cohesion, and its removal induces SAC activation. It has also been observed that other components of the ORC complex (such as orc5 in "S. pombe") are implicated in cohesion. However, the molecular pathway involving the ORC proteins seems to be additive to the cohesins' pathway, and it is mostly unknown.