Suddenly Wall Street is getting a bit nervous. Here are two ways to prepare for potential turbulence.

By Steve GoldsteinJPMorgan and Citadel Securities advise investors to take a cautious stanceMaybe it's time to get cautious in portfolios, leading strategists say.Maybe the expression should be "sell in June and go away." The S&P 500 SPX has meandered through a dud of a three-month period, rising j…