Cell Signaling and Cytoskeleton Mechanisms
1. Signaling Big Picture
- Cellular Response: Cells detect extracellular signals, measure ligand concentration, relay/amplify information, and trigger changes in enzyme activity, gene expression, secretion, cytoskeletal behavior, motility, survival, or cell-cycle progression.
- Intercellular Modes: Contact-dependent (juxtacrine), paracrine, synaptic, and endocrine. Synaptic signaling is local, fast, and low-affinity; endocrine is long-range, dilute, and usually high-affinity.
2. Receptor Classes
- Ion-Channel-
Cell Biology: Essential Principles of Membrane Transport
Cellular Compartments and Nuclear Transport
Like the lumen of the ER, the interior of the nucleus is topologically equivalent to the outside of the cell. (True)
Researchers in a biotechnology company have discovered a drug that blocks the ability of Ran to exchange GDP for GTP. What is the most likely effect of this drug on nuclear transport? (Nuclear transport receptors would be unable to release their cargo in the nucleus.)
What is the role of the nuclear localization sequence in a nuclear protein?
Read MoreSkin and Mucosal Immunity: Extracellular vs Intracellular
Extracellular Pathogens – Skin
When an extracellular pathogen enters through the skin, the innate immune system activates several responses to detect and eliminate it:
- Pathogen Recognition: Pattern Recognition Receptors (PRRs) like TLR2 and TLR4 detect Pathogen-Associated Molecular Patterns (PAMPs) on the pathogen’s surface.
- Inflammation: Macrophages and keratinocytes release pro-inflammatory cytokines (IL-1β, TNF-α) to recruit immune cells.
- Phagocytosis and Antigen Presentation: Macrophages and Dendritic