1. Cytoskeleton Cell Migration and Adhesion Team Members Facilitators
Marta Bechtel
Christine Hohmann
Cleo Hughes-Darden
John Navaratnam
Kenneth Samuel
Dayalan Srinivasan
Erika Whitney
Facilitators
Randy Phillis
Melissa Zwick

2. Background Information
Class Level: Intermediate Cell Biology
Student Homework Before Class:
- Complete a reading assignment
- Complete an on-line quiz
(please see handout for quiz)

3. Learning Goal & Outcome
Understand the role of the cytoskeleton in cell migration & adhesion.
Outcome:
Students will be able to predict the
effects of cytoskeletal changes on cell
migration & adhesion.

5. Metastasis Why do cells move?
Normal Tissue Development
Wound Healing
Normal Cell Function
Are there situations when cells move when
they should not?
Metastasis

6. A B
To move the boat to the RIGHT
Remove anchor A
Remove anchor B

7. Focal Adhesions: X cellular anchors to the extracellular space
membrane
cytoplasm
(inside)
extracellular
space
(outside)
extracellular matrix (ECM)
proteins
integrins
adaptor complex
Rho GTPases
actin
filament
LIM kinase
myosin II
direction of
myosin pulling
cofilin
cuts
actin
filaments X

8. Focal Adhesions: cellular anchors to the extracellular space
Outside of
Cell
extracellular matrix (ECM)
proteins
3) integrins lose
attachment!
cell
membrane
adaptor complex
adaptor complex
2) lack of tension
along actin!
cytoplasm
(inside)
actin
filament
Rho GTPase
actin
filament
Rho GTPase
LIM kinase
1) Cuts
actin
filaments
Cofilin
LIM kinase
myosin II
Cofilin
direction of
myosin pulling

9. A - trailing edge B- leading edge
direction of
cell migration
Which side of the cell would you predict cofilin to be most active?
(A or B)

10. What happens if cofilin cuts actin filaments at the “leading edge” of the cell?
Cell stops migration
Cell starts migration
Cell re-attaches to the Extracellular Matrix (ECM)

11. Which of the following mimics the effect of cofilin activity on cell-ECM adhesion:
Separation of Integrin from the ECM
Activation of LIM Kinase
Elimination of Myosin II : Actin interaction
A, B, C
A and C

12. Homework
Cilengitide is a drug that is thought to act by interfering with the binding of specific integrin proteins to extracellular matrix proteins.
It has been shown to be effective in treating breast cancer.
Using the diagram for cell motility, how do you think cilengitide may affect breast cancer cells?

14. Group (or homework) question # 2
Based on the model, you decide to use (interference) RNAi to reduce the function of the following genes. Predict the effects of each RNAi treatment on the activity of cofilin.
Answer = “active” or “inactive”.
LIM kinase
Rho GTPase
Myosin II

15. Open ended discussion question
The actin filaments in the cytoskeleton are critical for cell motility in normal and cancer cells. Conversion of cofilin from inactive to active is regulated by phosphorylation:dephosphorylation.
When cofilin is phosphorylated, it becomes inactivated. What is a likely outcome of the following on cell motility?
Blocking cofilin Phosphorylation
Enhancing cofilin Phosphorylation
Blocking the activity of LIMKinase

16. When integrins bind to the ECM to the leading edge of a mobile cell, which of the following occur?
A) true, B) false
Cofilin is active
Actin filaments are not cleaved
LIM kinase is inhibiting cofilin activity
Cells are able to migrate

18. Cofilin