I cannot speak to the IATA issue, although I have heard as much before that any IATA member *can* issue a paper ticket or check baggage onto any other IATA member. Others have brought up the Iran Air and Cubana issue before, and it does seem unlikely that USA companies could interline with them unless there was some sort of blanket IATA thing that they participated in by default.
I do believe that there are IATA coded fares (YY?) on some routes that are woefully expensive, but allow one to ticket virtually any carrier on the route. But I'm no expert on IATA, so that may be entirely wrong.
As far as AS' published interline agreements:
Code:
E-Ticket Interline Agreements
AA AC AF AM BA BR
CI CM CO CX DL EG
EI FJ HA HP HU JL
KE KL KS K5 LA LP
MH MW MX M5 NZ OZ
PR PZ QF SK SQ UA
US VA VW WP WS YV
3M 7H
Paper Ticket and Baggage Interline Agreements
MAY ISSUE TICKETS INCLUDING
AA AC AF AM AS AV AY AZ BA BR CA CI CM CX
DE DL EK FI FJ HA HR HU IB JJ JL KA KE KL
KS K5 LA LH LP LR LY MH MU MW NH NZ OO OZ
PR PZ QF SK SQ SU SV TA TN T0 UA US VA VS
VW WP WS XL YV 3M 4M 7H
MAY CHECK BAGGAGE TO
AA AC AF AM AS AV AY AZ BA BR CA CI CM CX
DE DL EK FI FJ HA HR HU IB JJ JL KE KL KS
K5 LA LH LP LR LY MH MU MW NH NZ OO OZ PR
PZ QF SK SQ SU SV TA TN T0 UA US VA VS VW
WP WS XL YV 3M 4M 7H
According to Expertflyer.com as of today.