Cell Biology | Cell Cycle Regulation

About this video

• Video Title: Cell Biology | Cell Cycle Regulation
• Channel: Ninja Nerd
• Speakers: Zach Murphy
• Duration: 00:39:36

Overview

This video explains the regulation of the cell cycle, focusing on the molecular mechanisms and checkpoints that control cell progression. It details the roles of growth factors, proto-oncogenes, tumor suppressor genes, cyclins, and cyclin-dependent kinases (CDKs) in ensuring proper cell division and maintaining genomic integrity. The lecture also touches on the consequences of dysregulation, such as cancer.

Key takeaways

• Cell Cycle Phases and Checkpoints: The cell cycle consists of interphase (G1, S, G2) and mitosis (prophase, metaphase, anaphase, telophase), with critical checkpoints at G1/S, G2/M, and metaphase/anaphase to regulate progression.
• Genes Regulating Proliferation: Proto-oncogenes stimulate cell proliferation, while tumor suppressor genes act as brakes to inhibit it or repair DNA damage.
• Growth Factors and Receptors: External signals like growth factors (mitogens) bind to cell surface receptors, initiating intracellular signaling cascades that ultimately promote cell cycle progression.
• Cyclins and CDKs: Cyclins and cyclin-dependent kinases (CDKs) form complexes that drive the cell cycle forward by phosphorylating key proteins, such as the retinoblastoma protein (RB).
• Tumor Suppressors (RB and p53): RB binds to the E2F transcription factor, preventing cell cycle progression until it's phosphorylated by CDK complexes. p53 acts as a crucial tumor suppressor that halts the cell cycle in response to DNA damage, promoting repair or apoptosis.
• Apoptosis: If DNA damage is irreparable, pro-apoptotic genes are activated to induce programmed cell death, preventing the propagation of damaged cells.
• Specific Cyclin/CDK Complexes: Different cyclin-CDK complexes (e.g., Cyclin D/CDK4/6, Cyclin E/CDK2, Cyclin A/CDK2, Cyclin B/CDK1) regulate specific transitions between cell cycle phases.
• Metaphase Checkpoint: This checkpoint ensures proper chromosome alignment and kinetochore attachment before anaphase, involving proteins like securin, separase, and the anaphase-promoting complex (APC).