Cheesy Manicotti

1 pkg. (8 oz) sliced mushrooms
2 cloves garlic, minced
3 egg whites
1 pkg. (10 oz) frozen chopped spinach, thawed, well drained
1 container (15 oz ricotta cheese
1 cup shredded mozzarella cheese, divided
1/3 cup grated parmesan cheese divided
1 pkg. (8 oz) manicotti shells (14 shells) cooked, drained
2 cups spaghetti sauce

Preheat oven to 350°. Spray large nonstick skillet with cooking spray. Add mushrooms and garlic; cook 5 min. on medium heat, stirring frequently. Remove from heat. Beat egg whites lightly in medium bowl. Add mushrooms mixture, spinach, ricotta cheese and half of each of the mozzarella and parmesan cheese; mix well. Spoon evenly into manicotti shells. Place in 9x13-inch baking dish, sprayed with cooking spray. Cover with spaghetti sauce. Bake 40 min. or until heated through. Top with remaining mozzarella and parmesan cheese; continue baking 5 min. or until mozzarella is melted.