Publicis Groupe plans to shut down the Leo Burnett Detroit subsidiary and close its office in Troy, Michigan, after losing key business from General Motors.

The agency plans to lay off 79 employees and permanently close its office on Big Beaver Road by Dec. 31, according to a WARN notice filed with the state.

The layoffs are the consequence of GM taking long-running accounts away from metro Detroit businesses as the Detroit-based automaker shuffles its advertising agencies. Leo Burnett lost the creative accounts for Buick, GMC and Cadillac.

Publicis Groupe maintains other GM business and a significant presence in metro Detroit, though the company declined to provide headcount.

“Detroit remains an important city for us, and we will continue to invest in our capabilities and offerings there,” a Publicis Groupe spokesperson said in a statement.

Earlier Friday, the automaker confirmed plans to lay off about 1,000 employees globally—most at the Global Technical Center in Warren, Michigan—in its latest round of restructuring. The company also cut 1,000 white-collar software jobs in August.

Other Detroit ad agencies have made layoffs recently as a result of GM’s new media strategy. Interpublic's MRM laid off 123 employees at its office in Birmingham last month, while Commonwealth/McCann eliminated 56 jobs in Detroit.

Also: McCann WorldGroup’s Detroit strategy after GM cutbacks

While Leo Burnett has dozens of offices globally, the Chicago headquarters will be its only U.S. location after the Troy office closes.