From 勤(つと)め (tsutome, “連(れん)用(よう)形(けい) (ren'yōkei, “stem or continuative form”) of the verb 勤(つと)める (tsutomeru, “to work”).”) + 先(さき) (-saki, “destination”).
つとめさき • (tsutome-saki) ←つとめさき (tutome-saki)?