AAA in weird 4-way pot live

[jshove87]

Playing in a 6-handed deep 1-2NL game UTG raises to $12. Comes to me on the button I have AcAh. The raiser hadn't been at the table for long but from what I had seen appeared to be loose and bad. The SB is tight and BB is loose. I smooth call $12 and both blinds call as well. Flop comes Ad3c5d. All 3 players check to me. Normally I'd bet here but all players seemed disinterested in the pot so I figured I'd check behind and disguise. Turn comes Th. SB checks BB leads $15 and UTG raises to 45. BB stack is $400 UTG $500 my stack $450. What's my line?