The revolving door keeps spinning at Motorola as the company’s Chief Strategy and Technology Officer Rich Nottenburg resigned late last week. Although the company officially said that Nottenburg is leaving the company to “return to the New York area to be with his family and pursue other opportunities,” some speculate that his departure comes under pressure from activist investor Carl Icahn, who recently strengthened his influence within Motorola’s board.

Former CEO Ed Zander appointed Nottenburg as chief strategy officer in 2004; he took over the company’s research and development programs last December, when Chief Technical Officer Padmasree Warrior left the company to take a position at Cisco.

The company continues to post losses at its handset unit, while it plans to break the company into two some time next year, also under pressure from Icahn.

Since former CEO Zander resigned in December, the company has undergone numerous changes at its executive level, including the heads of finance, technology, human resources, marketing and the head of its mobile devices unit.

Dan Moloney, who currently heads the home networks mobility business, will now also oversee Motorola Labs, the company’s research group.