I don't PvP much, but it's obvious that there is no such think as "threat" in PvP. How do tanks go about grabbing the attention of opposing players gunning for the objective or healers?
Cap a control point in front of them. If they're not brain-dead, they will attack you.
If they ARE brain-dead, GG U R MVP!!
If it's a point you already control, Stand. Right. On. Top. Of. It. And don't move!
You are the node boss mob. You don't path far from your spawn, and if someone tries to pull you away from your spawn, you quickly reset.