In large baking dish, toss vegetables and 1/2 cup salad dressing; cover. In small bowl, toss shrimp, and remaining dressing; cover. Marinate vegetables and shrimp 30 minutes; drain. Grill or broil vegetables until slightly brown, about 5 min per side. Grill or broil shrimp until pink, about 2 min per side. Cook pasta according to package directions; drain. Meanwhile, in large saucepan, stir together marinara sauce and vegetables, heat to boiling. Reduce heat; add shrimp and heat through. Toss hot pasta and sauce.