So following good agile practices, I would recommend that you ask the Product Owner for the other team where your item is on their backlog. Request an estimate for when they think it will be committed to a sprint.
If your dependent on a waterfall team then I would make the request to the project manager and functional manager for that team.
In either instance you need to clearly communicate when you need the functionality by. Let the team know if you don't have functionality by X date, your program would go to blocker state (Red on a standard stoplight dashboard). Then I recommend you also set up additional milestones for when your program will go to yellow based on risk the dependency won't be delivered.
One last related note. I generally don't recommend a scrum team start work on any story that has a dependency. If the dependency doesn't get filled, then that's wasted development work. It also impacts the teams ability to be "done" with that user story.