VO 6 cell biology

• The target of the drug used in clinical trials for cancer treatment is not specified
• The target of drug X is WEE1 (an inhibitor)
• Cohesin holds replicated sister chromatids together
• M-CDK activity triggers entry into mitosis
• Drug X used in clinical trials for cancer treatment targets WEE1
• Dephosphorylation activates M-Cdk at the onset of mitosis
• Cells achieve bipolar chromosome segregation during mitosis through appropriate chromosome structure, building the chromosome segregation machinery, and a system to ensure equal distribution of genetic information.
• The mitotic spindle, composed of microtubules, plays a crucial role in attaching sister chromatids to the spindle.
• Tension-generating attachments, cleavable subunits, cohesin rings, kinetochores, and cohesion are involved in triggering the bipolar segregation of chromosomes during mitosis.
• Separase is also involved in the process of bipolar chromosome segregation.
• S-Cdk initiates DNA replication once per cycle.
• Chromosome duplication requires duplication of chromatin structure, including the replication of chromatin proteins (histones, etc) and their proper assembly on the DNA.
• S-Cdks stimulate a large increase in the synthesis of the four histone subunits that form the histone octamers at the core of each nucleosome.
• Cell fusion experiments by Johnson and Rao concluded that the S-phase nucleus releases something that drives the G1 nucleus into S-phase.
• G2 nucleus is resistant to S-phase promoting factor.
• Cell cycle transitions can be adjusted to intra- and extracellular signals
• Kinase: An enzyme that adds phosphate groups to other molecules
• APC/C: An enzyme complex involved in protein degradation during the cell cycle
• Multiple layers of Cdk regulation allow tightly controlled and ordered cell cycle progression
• Cyclin X: A protein that binds to Cdk and regulates the cell cycle
• Protein degradation: The breakdown of proteins in a cell
• Chapter 17 of Molecular Biology of the Cell, 6th Edition covers the molecular biology of the cell cycle
• The cell cycle control system ensures proper DNA replication and division of the cell
• Protein synthesis: The process of creating proteins in a cell
• CKI: Cyclin-dependent kinase inhibitor, a protein that inhibits Cdk activity
• Phosphatase: An enzyme that removes phosphate groups from other molecules
• Cdk: A protein involved in the regulation of the cell cycle
• The cell cycle includes processes such as membrane structure, cytoskeleton, cell migration, and chromosome segregation
• Tension: The force exerted on sister chromatids by the spindle fibers during cell division.
• Ub (Ubiquitin): A small protein that marks proteins for degradation by the proteasome.
• Kinetochore: A protein structure on the centromere of a chromosome that attaches to spindle fibers during cell division.
• APC/C (Anaphase-promoting complex): A protein complex that triggers the separation of sister chromatids and the completion of mitosis.
• Cohesion: The force that holds sister chromatids together.
• Anaphase: The stage of cell division in which sister chromatids separate and move towards opposite poles of the cell.
• Separase: An enzyme that cleaves the cohesin protein, allowing sister chromatids to separate during cell division.
• How is separase activated to trigger anaphase? (Question)
• Securin: A protein that inhibits separase and prevents premature sister chromatid separation.
• Proteasome: A cellular structure that degrades proteins.
• Sister chromatids: Two identical copies of a chromosome that are held together by a centromere.
• Cohesin ring: A protein complex that holds sister chromatids together during cell division.