AK after a re-raise against our iso-raise

[linuxrocks]

UTG is a fish and lost his 20xBB twice now and is ready to throw one more short-stack. Button is solid and seems to be playing well. I have seen this twice today. How do you play AK after it gets re-raised when we are trying to isolate? It's slightly different from getting re-raised with out a limper. They know that it might get called by the shortie and they will have to show a hand.

PokerStars No-Limit Hold'em, $4 BB (6 handed) TightPoker converter

BB ($370.75)
UTG ($60)
MP ($311.15)
linuxrocks ($455.55)
Button ($479.70)
SB ($692.95)

Preflop: linuxrocks is CO with A[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/heart.gif[/img].
UTG calls $4, <font color="#666666">1 fold</font>, <font color="#CC3333">linuxrocks raises to $20</font>, <font color="#CC3333">Button raises to $60</font>, <font color="#666666">2 folds</font>, UTG folds, linuxrocks ??.