The White House on Friday announced the third departure of a high-level aide to first lady Michelle Obama.

Camille Johnston, Obama's director of communications, "will be leaving the White House for a position in the private sector," an official White House statement said, without saying where she was going.

An official Siemens Corp. statement described Johnston's new position as its vice president, corporate affairs, effective Sept. 7:

"In this position, she will be a member of the U.S. leadership team and will be responsible for developing, leading and implementing a comprehensive and integrated media plan for Siemens Corporation," which it says is moving its U.S. headquaters to D.C. from New York City.

The White House statement included this praise:

" 'Camille has become a trusted advisor to me and to the entire East Wing,' said First Lady Michelle Obama. 'From our first day in the White House when we opened the doors and greeted visitors, she has led a communications team that has developed creative and effective strategies for the Let's Move! campaign, our work on behalf of military families, arts and cultural events in the White House and our international agenda. Her dedication, calming presence and expertise have been invaluable. She will be missed, but we wish her all the best.' "

The White House statement also quotes Johnston:

' 'Being invited by Mrs. Obama to be a part of her East Wing team was a privilege for which I am incredibly grateful. It has been an honor and a pleasure to serve the First Lady and the President and to be a part of this historic Administration.' "

Johnston previously served as communications director to Tipper Gore and was senior vice president of communications for the Los Angeles Dodgers.

The earlier East Wing departures included Michelle Obama's first chief of staff, Jackie Norris, who left in June 2009 with little explanation, and her first social secretary, Desiree Rogers, who departed earlier this year after a couple crashed a White House party.

What is Siemens? The Germany-based company describes itself this way: "Siemens Corporation is a U.S. subsidiary of Siemens AG, a global powerhouse in electronics and electrical engineering, operating in the industry, energy and healthcare sectors. For more than 160 years, Siemens has built a reputation for leading-edge innovation and the quality of its products, services and solutions. With 405,000 employees in 190 countries, Siemens reported worldwide revenue of $104.3 billion in fiscal 2009."