ECM cell junctions

• What is the extracellular matrix (ECM)?

  A 3D mesh of proteins and carbohydrates
• What are the key components of the ECM?

  Collagen, elastin, fibronectin, proteoglycans
• What is one main function of the ECM?

  Holds cells together through adhesion
• How does the ECM influence cell behavior?

  It influences movement, growth, and specialization
• When is the ECM actively remodeled?

  During healing or cancer spread
• Which cells build connective tissue ECM?

  Fibroblasts
• What do osteoblasts create?

  Bone ECM
• What happens to bone ECM?

  It can calcify
• What diseases are linked to mutations in ECM proteins?

  Ehlers-Danlos and Cutis laxa
• How many types of cytoskeleton components are there?

  Three types
• What are the three types of cytoskeleton components?

  Microfilaments, Intermediate filaments, Microtubules
• What is the diameter of microfilaments (Actin)?

  7 nm
• What is the diameter of intermediate filaments?

  10 nm
• What is the diameter of microtubules?

  25 nm
• How are microfilaments structured?

  Built from G-actin monomers into F-actin
• What is the dynamic behavior of microfilaments?

  Constant assembly and disassembly (treadmilling)
• What role does profilin play in microfilaments?

  Encourages growth of microfilaments
• What does cofilin do?

  Promotes disassembly of microfilaments
• What do capping proteins do?

  Block growth at the + ends of microfilaments
• What is the role of myosin?

  Moves along actin, ATP-dependent
• What is the structure of microtubules?

  Made of α- and β-tubulin dimers
• What is dynamic instability in microtubules?

  Grow using GTP-tubulin, shrink with GDP
• What is one function of microtubules?

  Chromosome separation in mitosis
• How do motor proteins like kinesin and dynein function?

  Kinesin moves toward the + end, dynein toward - end
• What do kinesin and dynein carry?

  Cargo like vesicles and organelles
• What is the structure of intermediate filaments?

  Strong, rope-like filaments
• What is the main job of intermediate filaments?

  Provide structural support and anchor the nucleus
• How do intermediate filaments differ from microfilaments and microtubules?

  They are not dynamic and require no motors
• What do cell-cell junctions help with?

  Help cells stick, communicate, and form tissues
• What are the types of cell-cell junctions?

  Tight junctions, adherens junctions, desmosomes, gap junctions
• What do tight junctions do?

  Seal spaces between cells to prevent leakage
• Where are tight junctions commonly found?

  In epithelial sheets like intestines
• What do adherens junctions link to?

  Link to actin filaments
• What is the function of desmosomes?

  Provide strong mechanical strength
• Where are desmosomes commonly found?

  In the heart and skin
• What do gap junctions create?

  Channels between cells for communication
• What proteins make up gap junctions?

  Connexin proteins
• What are the main functions of the ECM?

  • Holds cells together (adhesion)
  • Stores and releases growth factors
  • Influences cell movement, growth, and specialization
  • Actively remodeled during healing or cancer spread
• What are the main functions of microfilaments (Actin)?

  • Cell movement (e.g., crawling)
  • Shape maintenance (e.g., microvilli)
  • Intracellular transport
  • Cell division (cytokinesis)
• What are the main functions of microtubules?

  • Chromosome separation in mitosis
  • Transport highways inside cells