I'm going to want to update to android 4.3 when it comes out. I have rooted my Nexus 4, flashed Paranoid Android and Franco Kernel. Can I just use Root Keeper to temporarily un-root, then install update from settings>about phone>system updates, and turn on root in Root Keeper? Ultimately I want to have the latest android and paranoid android version and keep all my data.
I also use Franco's kernel and run PAC, based largely on ParanoidAndroid. Unfortunately you won't be able to do an OTA update because it's not the root that breaks it, but the fact that you're really running a different kernel and OS. (In the case of PA, it actually automatically disables the OTA update feature to keep stuff from breaking).
That said, you can easily flash the 4.3 image using FastBoot when it's released - but remember, you'll lose all your PA and Franco goodness!
ParanoidAndroid will be updated to 4.3 when the devs get to it, which shouldn't take too long. I'm just gonna wait for them personally.
EDIT: Also remember that your kernel is compiled for 4.2, and probably won't work with 4.3. You may have to wait for Franco to update as well, or switch to another kernel.