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Full-Text Articles in Cell Biology

A Novel Autophagy Regulatory Mechanism That Functions During Programmed Cell Death: A Dissertation, Tsun-Kai Chang Sep 2013

A Novel Autophagy Regulatory Mechanism That Functions During Programmed Cell Death: A Dissertation, Tsun-Kai Chang

GSBS Dissertations and Theses

Autophagy is a cellular process that delivers cytoplasmic materials for degradation by the lysosomes. Autophagy-related (Atg) genes were identified in yeast genetic screens for vehicle formation under stress conditions, and Atg genes are conserved from yeast to human. When cells or animals are under stress, autophagy is induced and Atg8 (LC3 in mammal) is activated by E1 activating enzyme Atg7. Atg8-containing membranes form and surround cargos, close and mature to become the autophagosomes. Autophagosomes fuse with lysosomes, and cargos are degraded by lysosomal enzymes to sustain cell viability. Therefore, autophagy is most frequently considered to function in cell survival. Whether ...


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 ...