Answer
Yes, Karl-Theodor zu Guttenberg served in Angela Merkel's cabinet. He was appointed Minister of Defence in 2009, but resigned in 2011 after it was revealed that he had plagiarized his doctoral dissertation. Guttenberg was a member of the Christian Democratic Union (CDU), and was one of Merkel's most trusted allies. His resignation was a blow to Merkel's government, and it led to a period of political instability in Germany.