FCH/Cdc15 domain determines distinct subcellular localization of NOSTRIN

NOSTRIN, an NO synthase binding protein, belongs to the PCH family of proteins, exposing a typical domain structure. While its SH3 domain and the C-terminal coiled-coil region cc2 have been studied earlier, the function of the N-terminal half comprising a Cdc15 domain with an FCH (Fes/CIP homology) region followed by a coiled-coil stretch cc1 is unknown. Here, we show that the FCH region is necessary and sufficient for membrane association of NOSTRIN, whereas the Cdc15 domain further specifies subcellular distribution of the protein. Thus, the FCH region and the Cdc15 domain fulfill complementary functions in subcellular targeting of NOSTRIN.