NIP1/XB51/NECAB3 is a potential substrate of Nek2, suggesting specific roles of Nek2 in Golgi

Abstract

Nek2 is a mammalian protein kinase structurally homologous to Aspergillus NIMA. We previously observed that the Nek2 protein was localized in multiple sites within a cell in a cell cycle stage-specific manner. Such dynamic behavior of Nek2 allowed us to propose that Nek2 may be a mitotic regulator that is involved in diverse cell cycle events. To better understand the cellular processes in which Nek2 participates, we carried out yeast two-hybrid screening and isolated Nek2-Interacting Protein 1 (NIP1), which has been also named as XB51 and NECAB3. Physical interactions of Nek2 with NIP1 were confirmed. In fact, Nek2 can phosphorylate NIP1 in vivo. Immumostaining experiments revealed that NIP I is a Golgi protein. These results propose a possible involvement of Nek2 in biological processes of the Golgi body, perhaps in relation to the inheritance of Golgi during mitosis or to cell cycle stage-specific regulation of exocytosis. (C) 2003 Elsevier Inc. All rights reserved.