* Payrolls data on tap
* Gap falls in premarket after August sales
* Prana Biotech jumps on orphan drug designation
* Futures off: Dow 53 pts, S&P 6.75 pts, Nasdaq 6 pts
By Chuck Mikolajczak
NEW YORK, Sept 5 (Reuters) - U.S. stock index futures fell on Friday, putting the S&P 500 on track for its first lower week out of five, as investors awaited the monthly employment report.
* The benchmark index has fallen for three straight sessions since closing at a record high of 2,003.37 a week ago. Both the Dow Industrials and S&P 500 managed to touch fresh intraday highs on Thursday, before weakness in energy shares caused major indexes to retreat.
* Investors were looking ahead to the August jobs report, due at 8:30 a.m. EDT (1230 GMT), to assess the economy's strength and possible timing of an interest rate hike by the Federal Reserve. Estimates call for nonfarm payrolls to rise to 225,000 and the unemployment rate to fall to 6.1 percent. A reading above 200,000 would mark the seventh straight month at such a pace, a streak not seen since 1997.
* S&P 500 e-mini futures were down 6.75 points and fair value - a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract - indicated a lower open. Dow Jones industrial average e-mini futures fell 53 points and Nasdaq 100 e-mini futures lost 6 points.
* Michael Kors shares lost 4.4 percent to $76.49 before the opening bell. The company announced a 11.6 million share secondary offering on behalf of one of its principal founding shareholders, which will result in the resignation of two board members.
* Gap Inc shares lost 5.9 percent to $43.85 in premarket after the retailer posted worse-than-expected August same-store-sales.
* U.S.-listed shares of Prana Biotechnology surged 21 percent to $2.59 in premarket trade after the company said it received an orphan drug designation for its Huntington Disease treatment.
* European stocks fell as traders cashed in on recent gains, fueled by fresh monetary stimulus in Europe, and awaited U.S. jobs data.
* In Asia, Japan's Topix stalled just shy of its January high, while Chinese stocks extended a rally, with the CSI300 climbing to its highest in over eight months. (Editing by Bernadette Baum)