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Hoi-Yeung Li

Publications and source records attributed to Hoi-Yeung Li.

3 recordsLinked to original sources
PubMed2004

The production and localization of GTP-bound ran in mitotic mammalian tissue culture cells.

The RanGTPase system has multiple functions in both interphase and mitosis. Extensive studies of Ran-driven nucleocytoplasmic transport have contributed significantly toward our understanding of how RanGTP is produced, hydrolyzed, and localized in interphase. However, there is still a lack of understanding about how this system operates in mitosis. Recent advances have begun to shed light on how RanGTP is produced and localized in mitotic mammalian cells.

Animals↗
PubMed2004

Phosphorylation of RCC1 in mitosis is essential for producing a high RanGTP concentration on chromosomes and for spindle assembly in mammalian cells.

Spindle assembly is subject to the regulatory controls of both the cell-cycle machinery and the Ran-signaling pathway. An important question is how the two regulatory pathways communicate with each other to achieve coordinated regulation in mitosis. We show here that Cdc2 kinase phosphorylates the serines located in or near the nuclear localization signal (NLS) of human RCC1, the nucleotide exchange factor for Ran. This phosphorylation is necessary for RCC1 to generate RanGTP on mitotic chromosomes in mammalian cells, which in turn is required for spindle assembly and chromosome segregation. Moreover, phosphorylation of the NLS of RCC1 is required to prevent the binding of importin alpha and beta to RCC1, thereby allowing RCC1 to couple RanGTP production to chromosome binding. These findings reveal that the cell-cycle machinery directly regulates the Ran-signaling pathway by placing a high RanGTP concentration on the mitotic chromosome in mammalian cells.

Animals↗
PubMed2003

Ran in the spindle checkpoint: a new function for a versatile GTPase.

The small GTPase Ran has a well-established role in nucleocytoplasmic trafficking. In recent years, the repertoire of Ran has expanded to include regulation of spindle assembly, formation of the nuclear envelope and DNA replication. Now, new studies further extend the role of Ran to regulating the spindle checkpoint during mitosis.

Animals↗