Transport and communication across the nuclear envelope

Abstract

Nuclear envelope (NE), a double-membrane subcellular structure, encloses the genomic DNAs in nucleus and facilitates the effective transport and communication between nucleus and cytoplasm. Nuclear pore complexes form the selective transport channels across the nuclear envelope and coordinate the active gene expression and mRNA export with the cytoplasmic signaling. Nuclear outer and inner membrane proteins such as the LINC complexes and the LEM-domain proteins establish the connections among cytoplasmic skeletons, nuclear lamina, and chromatins; and the extensive networks contribute to the nuclear mechanical support, perinuclear chromatin organization, gene expression regulation, etc. Nuclear envelope undergoes dramatic dynamics during the open mitosis of higher eukaryotes, and the assembly and organization of the NE-associated proteins are tightly controlled through the cell cycle. NE protein malfunctions have been linked to various human diseases that roughly fall into two classes: The nuclear pore complex-related diseases and the nuclear lamina and inner membrane proteins- associated diseases (laminopathies). Over the past decade, structural elucidations of the NE proteins at the atomic or near-atomic resolution have greatly enriched our knowledge of the physiologic and pathologic mechanisms of the nuclear envelope functions. This chapter reviews recent breakthroughs in the structural understanding of NE proteins and their functions in nucleocytoplasmic transport, nuclear envelope organization, the dynamic mitotic NE reestablishment, the NE-associated pathogenesis and others.