1. Preheat grill to medium-high heat.
2. Coat mushrooms, onion, corn, bell pepper, zucchini, and yellow squash with cooking spray. Arrange vegetables on grill rack coated with cooking spray. Grill 5 minutes on each side or until tender.
3. Combine oil and next 5 ingredients (through black pepper) in a large bowl, stirring with a whisk. Cut kernels from ears of corn; add to oil mixture. Cut remaining vegetables into bite-sized pieces; add to oil mixture. Toss gently to combine. Top with cheese and pine nuts.