One of Motorola's longest-serving senior executives is leaving, another sign of the phone maker's continued struggles.

Jim Wicks, who has led the design team at Motorola Mobility for a dozen years, is joining the faculty at Northwestern University's McCormick School of Engineering in July.

He is the second top exec to leave Motorola recently. Rick Osterloh, another veteran, who was based in Silicon Valley and most recently was president of Motorola, left in March and soon was hired to run Google's hardware division.

The departures of Wicks and Osterloh underscore the wrenching changes Motorola Mobility has undergone in recent years. It was spun off from the rest of Motorola in 2011, then purchased by Google a year later. Google gave Motorola the financial cushion it had been lacking after its market share began to plummet in the late 2000s, when the halo of the popular Razr line of phones began to fade and the recession put stress on the company's ability to absorb continued losses.

But Google was more interested in Motorola's patents than running its phone business. Lenovo, a Chinese computer maker, bought Motorola two years later. There were high hopes that the company could reboot under new owners.

The phone maker moved from Libertyville to River North but nonetheless continued to shrink. When Google bought it, the company employed about 3,000 people in the Chicago area. By the time it arrived at the Merchandise Mart in 2014, there were 2,000. A brief honeymoon filled with hopes of building around Motorola's engineering and sales talent in Chicago, ended when the company's phone business suffered a sharp decline, especially in its home market, and Lenovo cut about 500 jobs last year.

Despite all the turmoil, Motorola's senior leadership remained intact, with Osterloh leading the business, Wicks heading up design and Iqbal Arshad leading engineering. With Wicks and Osterloh gone, the question is how long others will remain.

Wicks, who was Motorola's senior vice president of consumer experience design, will be on the faculty at the Segal Design Institute at Northwestern. The University of Illinois graduate joined Motorola in 2001 from Sapient after a career as a designer for Sony. Based in Chicago, he worked on some of Motorola's most well-known products, including the Razr, Droid and Ming phones. The Ming, a touch-screen device sold in China, predated the iPhone.

"We greatly appreciate Jim's contributions in leading a consumer experience design team that delivered standout, iconic, and award-winning industrial design and user experiences for Moto's mobile and wearable products," said Aymar de Lencquesaing, chairman of Motorola Mobility and co-president of Lenovo's mobile business group. "We wish Jim well as he enters this new phase in his career.

"To move us forward, we have an ideal leader on board, Ruben Castano, who will continue our design team's success. We are very confident in Ruben's talent, leadership and proven track record in defining design strategies that will continue to shape the Moto brand worldwide."

Castano, who led Lenovo's MBG Design Studio in Sao Paulo, has held several design leadership roles at Motorola since 2005. He will be based in Chicago.