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

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)

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.

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

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

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

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

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)

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)

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

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?

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

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

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

Cofilin