KEATON AND STREEP A TERRIFIC SISTER ACT.

Byline: Bob Strauss Daily News Film Critic

Sisterhood proves powerful in ``Marvin's Room.'' As long as its a sisterhood of great actresses, anyway, that has the power to transcend a rather trite and obvious, if heartfelt, scenario.

Sister acts simply don't get any better than Meryl Streep and Diane Keaton, together again here for the first time (they both appeared in Woody Allen's ``Manhattan,'' but never in the same scene). Streep is the bad sister, Lee, a naturally tough, ineffectively controlling single mother with one nice young son (Hal Scardino) and a teen-ager, Hank (Leonardo DiCaprio), who burns down the family home at the start of the movie. Hank's quite possibly the only person on Earth whose life is fueled by more rage than his mother's.

Anyway, Lee and her boys have scraped by up North for some 20 years while her nice sister, Keaton's Bessie, has stayed in Florida caring for their father, Marvin (Hume Cronyn, all grunts and facial hair), now bedridden after a stroke, and his doddering sister, Ruth (Gwen Verdon).

Never married, Bessie has served her elders without complaint. She was evidently just as comfortable staying out of contact with her sister or nephews. When Bessie is diagnosed with leukemia, however - co-producer De Niro plays the small role of her distracted doctor - she finally reaches out. Seeing as how they have nowhere else to go, Lee has no good argument against coming to Orlando to see if she or one of her sons could be a bone-marrow donor.

Once Lee finds herself back in the old family hothouse, however, she has no trouble inventing reasons why she can't stay. But despite all of the old relationship scabs that get scratched, there's little question as to which ties will end up binding whom.

The late Scott McPherson wrote the stage play ``Marvin's Room'' is based on as a kind of tribute to the caring he and his lover shared when they came down with AIDS. The screenplay (McPherson's also) cannot be faulted for the way it appreciates such giving, and it does boast a nice strain of humor and many sharp insights into family conflicts, along with a lot of good dialogue.

But the interpersonal resentments, sudden emotional crises and sentimental resolutions to just about every problem the story stirs up are as familiar as they are when Valerie Bertinelli goes through them in a TV movie.

An ABC-TV movie, to be specific. Although ``Marvin's Room'' marks a decent enough film-directing debut for Broadway super-stager Jerry Zaks (``Guys and Dolls,'' ``Smokey Joe's Cafe''), he never should have let a blatant advertisement for Walt Disney World intrude on this otherwise intimate experience. A trip to the Magic Kingdom is apparently mentioned in the play, but in a life-and-death drama released by Disney's art-movie subsidiary Miramax, it's just not a good idea to show Meryl Streep romping around Cinderella's castle.

Of course, Streep, Keaton and DiCaprio can make even the stalest scene appear fresh and glistening. Streep avoids the usual pitfalls classy actresses stumble into when they play a working-class hard case. Lee's neither covering up too much vulnerability nor genuinely insensitive, and even though she's proudly just graduated from beauty school, she ain't no dummy, either.

DiCaprio, who's been talked up as the guy for a James Dean bio film ever since he started shaving, gets to test-drive that troubled teen rebel schtick across all lanes of traffic and past several state lines here, too. Sometimes, he can make Hank so dog mean you almost think - and kind of hope - this brat is beyond redemption. In a bolder piece, maybe he would be.

But Keaton is ``Marvin's Room's'' greatest survivor. Banishing all of her traditional ticks (or maybe she just exhausted the supply making ``The First Wives Club''), Keaton presents a marvelously tensile portrait of a woman who hasn't done much with her life, but gotten more out of it than most of us can claim. Yes, of course, Bessie's the open, beating heart of ``Marvin's Room,'' but Keaton makes her far more than just an organ of a schematic play.

She makes a dying woman breathe, and by that brings abundant life to a film that might otherwise have suffocated itself.

THE FACTS

The film: ``Marvin's Room'' (PG-13; language).

The stars: Meryl Streep, Diane Keaton, Leonardo DiCaprio, Robert De Niro, Gwen Verdon, Hume Cronyn.

Behind the scenes: Directed by Jerry Zaks. Written by Scott McPherson, based on his play. Produced by Scott Rudin, Jane Rosenthal and Robert De Niro. Released by Miramax Films.

Running time: One hour, 36 minutes.

Playing: United Artists, Westwood.

Our rating: Three Stars.

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Photo

Photo: Diane Keaton, left, and Meryl Streep play sisters reunited by a fatal disease in ``Marvin's Room.''