AutoNation has laid off 145 of the 650 workers at its headquarters in Fort Lauderdale, Fla., as part of a reorganization. In addition, the company, the nation's largest auto retailer, has warned 50 other workers that their jobs may not last long, AutoNation spokesman Jim Donahue said. In January, AutoNation will spin off its $3.6-billion car rental arm as a new company, ANC Rental Corp., which will include the Alamo, National and CarTemps USA brands. The company announced last week that it has reversed its decision to move the headquarters for the rental group from Fort Lauderdale to Minnesota. AutoNation is controlled by billionaire H. Wayne Huizenga.