* Futures down: Dow 145 pts, S&P 17 pts, Nasdaq 33 pts
By Tanya Agrawal
Aug 31 (Reuters) - U.S. stock index futures were lower on Monday as investors once again turned their focus to the possibility of a September interest rate increase.
* Weekend comments from Federal Reserve Vice Chairman Stanley Fischer appeared to keep the door open for a rate hike next month.
* U.S. inflation will likely rebound as pressure from the dollar fades, allowing the Fed to raise interest rates gradually, Fischer told CNBC at the global central banking conference in Jackson Hole, Wyoming.
* Fischer's comments suggest the Fed could look beyond a week of stock market turmoil brought on by fears that China's economy is faltering.
* Wall Street closed flat on Friday after a tumultuous week that featured both the market's worst day in four years and biggest two-day gain since the financial crisis.
* Chinese shares had another volatile session on Monday. The Shanghai Composite lost 0.8 percent, while the blue-chip CSI300 index ended up 0.7 percent. Both were down more than 4 percent at one point.
* The two indexes lost about 12 percent for the month, and nearly 40 percent since mid-June despite repeated and unprecedented measures by the government to shore up the market.
* Investors will be keeping a sharp eye on economic data again this week, especially the monthly jobs report on Friday, the last one before the Fed meets on Sept. 16-17.
* The U.S. central bank has said it will raise rates only when it sees a sustained recovery in the economy. While the job market has improved steadily, inflation has remained below the central bank's 2 percent target for more than three years.
* J. C. Penney shares were up 3.8 percent at $9.28 in premarket trading after Deutsche Bank raised its rating to "buy" from "hold".
* Twitter was up 2.1 percent at $27.45 after SunTrust Robinson raised its rating to "buy" from "neutral".
Futures snapshot at 7:13 a.m. ET (1113 GMT):
* S&P 500 e-minis were down 17.25 points, or 0.87 percent, with 210,496 contracts traded.
* Nasdaq 100 e-minis were down 32.5 points, or 0.75 percent, on volume of 38,845 contracts.
* Dow e-minis were down 145 points, or 0.87 percent, with 25,048 contracts changing hands. (Reporting by Tanya Agrawal; Editing by Saumyadeb Chakrabarty)