From reports on the AA and UA boards, the tunnel at LAX from T-4 to T-5 is now open, and the AS website page for LAX no longer indicates that there's a shuttle from T-6 to T-4 for connecting pax.

So, if you're connecting from AS to AA and need to switch terminals in Los Angeles, head downstairs in T-6 and look for signage that will send you to the tunnel to T-5 and then there should be another tunnel that takes you to T-4.

Reports are that it's about a 10 minute walk or thereabouts.

Then again, since AA is taking over some gates in T-6, your connection just might be in the same terminal as AS!