Not in the cleric section. 3e was the last edition that had clerics lose their powers RAW. There is nothing in 4e about it either, but I think you had to retrain your channel divinity feat if you switched deities...
In 4e, clerics specifically did not lose their powers if they turned against their patron deities.
Exactly! Actual superpowers have to come from somewhere.
This is what 4e says on the topic, and I find it to be a perfectly cromulent explanation:
"As a cleric, your deity does not directly grant you powers. Instead, your ordination or investiture as a cleric grants you the ability to wield divine powers. Clerics are usually formally ordained by existing clerics who perform a special ritual to do so, but on rare occasions a deity moves to directly ordain a worthy worshiper without any sort of priestly hierarchy involved. What you do with your powers once you are ordained is up to you, although if you flagrantly and openly defy your deity’s tenets, you quickly earn the enmity of the faithful."
(The Paladin description focuses a bit more on personal devotion and rites, but essentially says the same thing).
I like this approach. It means that priestly hierarchies are probably going to be screening potential clerics pretty strongly before ordaining them – because once granted, ordination is not a gift that can be taken back. And should a cleric be misbehaving, it's up to the faithful to deal with the problem. The deity can't be bothered with individual priests.
I think this approach creates much more interesting story opportunities, particularly two: the Heretic and the Apostate.
The Heretic is a character who still considers themselves faithful to their deity, but disagree with other faithful on matters of doctrine. Since both sides are getting divine juice, you can't tell which side is right by seeing who gets to keep their powers.
The Apostate is a character who has actively turned away from their deity, but who are still using the deity's powers to fight that deity's followers. This could go both ways – just like you could have a fallen priest of Pelor, you could have a redeemed priest of Bane.
