Yes it can autofocus ... kind of. The depth of field of a DSLR is much thinner than a traditional video camera, so the focus has much less leeway in getting it right, and you notice if it's not right. Additionally, AF-S lenses can't power back and forth very quickly to check focus through the contrast detect AF system, unlike lenses with micromotors, which can do that, which slows down focus even further. So the AF works, but the performance is sluggish compared to a dedicated video camera.
Nikon's better choice if you want AF in video are the V1 and V2, which also take the ME-1, but have a smaller sensor and phase detect autofocus during video. That said, the D3200 is much better for stills, and if you already own the D3200, go and try out how the video system works!