Cell motility in physiology and pathology
iRAT questions week 1:
1. Fibroblasts seem to lay as single cells embedded into the extracellular matrix
(ECM) present in connective tissue. However, the fibroblasts do make cell-
cell junctions between each other. Which cell-cell junctions are present
between fibroblasts? —> gap junctions. They are single cells that produce the
proteins of the ECM. The gap junctions allow the exchange of small molecules
2. Hemidesmosomes are formed by ___ and connect an epithelial cell with ___ . —
> integrins, the basement membrane
3. Integrins are cell-ECM adhesion receptors and can bind to many different
ECM molecules. Which of the following is NOT an ECM protein, and
therefore NOT an integrin ligand? —> lamin. It is in the nuclear envelope. Laminin
is located in the basement membrane.
4. Cadherin-cadherin and integrin-ECM interactions differ in terms of binding
strength or active/inactive molecular state, with possible consequences for
migration. Which of the following statements is NOT true? —> Cadherins can
bind to other cadherins as well as to ECM molecules of the basement membrane to
generate epithelial stability.
• For 2 epithelial cells to separate from each other, E-cadherin may be downregulated
or degraded. This may allow cell migration across other epithelial cells or away from
the epithelium.
• In fibroblasts, integrins may be downregulated or degraded. This may change cell
migration rates within ECM.
• Integrin activation/ de-activation events are sufficient to change cell- ECM adhesion
strength. This may change cell migration rates.
,5. Which fibrillar protein does not form the cells cytoskeleton? —> collagen
fibers. Cytoskeleton: Intermediate filaments, Actin cytoskeleton, Microtubules
6. What is the correct order of the migration steps of a mesenchymal cell
moving over a 2D surface? —> Protrusion, adhesion, contraction, rear retraction
7. Which of the following state to about the contraction of skeletal muscle is
correct? —> The power stroke of skeletal muscle contraction occurs when the
myosin head releases Pi.
8. Ca2+ released into a myofibril by the action of a nerve impulse binds to a site
on ___ , in order to initiate skeletal muscle contraction. —> troponin
9. Which of these statements about the protein calmodulin is correct? —>
Protein in the cytoplasm of smooth muscle that binds calcium. Calcium-bound
calmodulin interacts with myosin light chain kinase and phosphorylates myosin light
chain leading to actin contraction.
10. Which out of the following statements is true about G-protein coupled
receptors? —> The N-terminal chain is extracellular and C-terminal chain is
intracellular
,Lecture I: intracellular determinants of migration
Actin filament-based structures
- Migration-associated actin filaments
1. Molecular actin filament organization/dynamics
Actin globular filaments form dynamic actin filaments
, Really energy consuming process: up to 50% of total ATP consumption my be used
for actin polymerization.
iRAT questions week 1:
1. Fibroblasts seem to lay as single cells embedded into the extracellular matrix
(ECM) present in connective tissue. However, the fibroblasts do make cell-
cell junctions between each other. Which cell-cell junctions are present
between fibroblasts? —> gap junctions. They are single cells that produce the
proteins of the ECM. The gap junctions allow the exchange of small molecules
2. Hemidesmosomes are formed by ___ and connect an epithelial cell with ___ . —
> integrins, the basement membrane
3. Integrins are cell-ECM adhesion receptors and can bind to many different
ECM molecules. Which of the following is NOT an ECM protein, and
therefore NOT an integrin ligand? —> lamin. It is in the nuclear envelope. Laminin
is located in the basement membrane.
4. Cadherin-cadherin and integrin-ECM interactions differ in terms of binding
strength or active/inactive molecular state, with possible consequences for
migration. Which of the following statements is NOT true? —> Cadherins can
bind to other cadherins as well as to ECM molecules of the basement membrane to
generate epithelial stability.
• For 2 epithelial cells to separate from each other, E-cadherin may be downregulated
or degraded. This may allow cell migration across other epithelial cells or away from
the epithelium.
• In fibroblasts, integrins may be downregulated or degraded. This may change cell
migration rates within ECM.
• Integrin activation/ de-activation events are sufficient to change cell- ECM adhesion
strength. This may change cell migration rates.
,5. Which fibrillar protein does not form the cells cytoskeleton? —> collagen
fibers. Cytoskeleton: Intermediate filaments, Actin cytoskeleton, Microtubules
6. What is the correct order of the migration steps of a mesenchymal cell
moving over a 2D surface? —> Protrusion, adhesion, contraction, rear retraction
7. Which of the following state to about the contraction of skeletal muscle is
correct? —> The power stroke of skeletal muscle contraction occurs when the
myosin head releases Pi.
8. Ca2+ released into a myofibril by the action of a nerve impulse binds to a site
on ___ , in order to initiate skeletal muscle contraction. —> troponin
9. Which of these statements about the protein calmodulin is correct? —>
Protein in the cytoplasm of smooth muscle that binds calcium. Calcium-bound
calmodulin interacts with myosin light chain kinase and phosphorylates myosin light
chain leading to actin contraction.
10. Which out of the following statements is true about G-protein coupled
receptors? —> The N-terminal chain is extracellular and C-terminal chain is
intracellular
,Lecture I: intracellular determinants of migration
Actin filament-based structures
- Migration-associated actin filaments
1. Molecular actin filament organization/dynamics
Actin globular filaments form dynamic actin filaments
, Really energy consuming process: up to 50% of total ATP consumption my be used
for actin polymerization.
