A guildmate of mine did some research on the subject, I will repost it for you:
Was browsing 4K tv's this weekend and one of the things I started thinking about was when it will be worth it to buy one and if the PS4 would be a future proof content provider for 4K.
Based on this article the answer is no.
I never played much PS3, but it still had value for me because it was the blue ray/media player for my living room. The games never looked that good on a 65" tv, but if it was at 4K resolution I could easily see myself gaming on it more.
It's not out of the question for PS4 to have a patch later down the road so it can translate 4K content or play blu-ray discs that have a compressed version of 4K content. Especially since 4K is pretty much Sony's baby, it would behove them to make the PS4 the premiere 4K "receiver" for lack of a better term.
Also, this is more a concern for those that prefer large screens in the 55+ range or sit closer to their TV's. Anyone that uses a PS4 on a 40" monitor or less and doesn't plan to go bigger, I wouldn't worry about it.
-- One thing to keep in mind with the above analysis. Its written from the perspective of folks that have do a lot of PC gaming. So comparisons to 65 inch TVs are subjective. Many of us play on PCs with 3 screens (6024x1080) and have really tremendous refresh and Ultra graphic settings on. The writer makes a very good point that its not out of the question to translate it.. but it won't be pure 4k in my mind which is like trying to take 720p and translate it up to 1080p... its doable, but its not native.