Her agent, Eric Stevens, tells the Los Angeles Times that Rubinstein died Wednesday at a Los Angeles hospital. Stevens says she recently suffered a heart attack.
(Watch the obituary CBS News Station KCBS-TV in Los Angeles aired on Rubinstein below)
Rubinstein made her film debut in the 1981 comedy "Under the Rainbow" and went on to roles in "Sixteen Candles," "Southland Tales" and the TV show "Picket Fences." She returned for both "Poltergeist" sequels.
The Pittsburgh native also appeared as the mother figure in a high-profile mid-1980s AIDS public awareness campaign and was an outspoken activist for the rights of little people.