BERLIN — Joachim Kosack, managing director of ProSiebenSat.1’s flagship channel Sat.1, is defecting to entertainment giant UFA to head the group’s TV and film production unit.

Kosack joins Nico Hofmann and Juergen Schuster in overseeing the newly formed Teamworx UFA arm, which encompasses TV divisions UFA Fernsehproduktion and Teamworx plus feature production shingle UFA Cinema. Kosak takes up the post in October.

ProSiebenSat.1 has tapped Nicolas Paalzow, chief exec of Cologne-based MME Entertainment, a subsidiary of the U.K.’s All3Media, to replace Kosack. Paalzow was managing director of the group’s ProSieben channel from 2000 to 2004.

For Kosak, who oversaw such Sat.1 productions as “The Pillars of the Earth” and hit series “Danni Lowinski” and “The Last Cop,” it’s a return to familiar ground. He worked as a writer, director and producer at UFA subsid Grundy UFA from 1996 to 2001, and was a producer at Teamworx through 2006. He joined ProSiebenSat.1 in 2006 and became Sat.1 managing director in 2011.

The move follows UFA’s restructuring of its various divisions, and the exits of longtime UFA co-managing director and producer Norbert Sauer and UFA Cinema topper Thomas Friedl.

Sauer steps down after more than 30 years at UFA. Friedl, former distribution chief at Constantin Film, joined UFA in 2008 to help launch the new UFA Cinema division.

While it initially unveiled an impressive production slate, UFA Cinema has suffered a number of disappointing releases.

The company is producing Philipp Stoelzl’s “The Physician,” an adaptation of Noah Gordon’s bestseller starring Ben Kingsley, Stellan Skarsgard and Tom Payne, and “Hanni & Nanni 3,” UFA’s latest installment in its modern adaptation of Enid Blyton’s 1940s children’s book series “St. Clares,” about twin sisters at a boarding school.