This domain is found at the C-terminus of protein phosphatase 1 regulatory subunits 12A, 12B and 12C. In protein phosphatase 1 regulatory subunit 12A it has been found to bind to cGMP-dependent protein kinase 1 via a leucine zipper motif located at the C-terminus of this domain [1-2].

1: Dimerization of cGMP-dependent protein kinase 1alpha and the myosin-binding subunit of myosin phosphatase: role of leucine zipper domains. Surks HK, Mendelsohn ME; Cell Signal. 2003;15:937-944. PMID:12873707

2: Regulation of myosin phosphatase by a specific interaction with cGMP- dependent protein kinase Ialpha. Surks HK, Mochizuki N, Kasai Y, Georgescu SP, Tang KM, Ito M, Lincoln TM, Mendelsohn ME; Science. 1999;286:1583-1587. PMID:10567269