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Full-Text Articles in Cell Biology

Nuclear Import Of Smad: A Dissertation, Xiaochu Chen Aug 2011

Nuclear Import Of Smad: A Dissertation, Xiaochu Chen

GSBS Dissertations and Theses

Signal transduction by transforming growth factor β (TGF-β) cytokines is mediated by an evolutionarily conserved mechanism that depends on the Smad proteins to transduce an extracellular stimulus into the nucleus. In the unstimulated state, Smads spontaneously shuttle across the nuclear envelope and distribute throughout the cell. Upon TGF-β or bone morphogenetic protein (BMP) stimulation, the receptor-activated Smads are phosphorylated, assemble into complexes with Smad4, and become mostly localized in the nucleus. Such signal-induced nuclear translocation of activated Smads is essential for TGF-β–dependent gene regulation that is critical for embryonic development and homeostasis. The molecular machinery responsible for this process ...


The Importance Of The Centrosomal Localization Sequence Of Cyclin E For Promoting Centrosome Duplication: A Dissertation, Joshua J. Nordberg May 2011

The Importance Of The Centrosomal Localization Sequence Of Cyclin E For Promoting Centrosome Duplication: A Dissertation, Joshua J. Nordberg

GSBS Dissertations and Theses

This thesis comprises three separate studies that investigate the consequences of supernumary centrosomes, the effect of centrosome loss, and a control mechanism for regulating CDK2/cyclin E activity in centrosome duplication.

The centrosome is the major microtubule-organizing center of the cell. When the cell enters mitosis, it is of critical importance that the cell has exactly two centrosomes in order to properly segregate the chromosomes to two daughter cells. Supernumary centrosomes are a problem for the cell in that they increase the incidence of chromosomal instability. Aberrant centrosome numbers are seen in a number of cancers, and there has been ...