Tao Lin and Jasneet Kaur

Lab Advisor: Dr. Edward Bonder

Teaching Assistant: Susan Seipel

Is there a correlation

between spindle orientation in

mitotic cells and the contracted

cell shape caused by the

GTPase protein, RhoA?

RhoA

mDiaRho kinase

Myosin phosphatase

LimK

Cofilin

Actin-myosin filament stabilization

MLC-p MLC

Actin polymerization

Unbranched filaments

Stress fibers

Actin-myosin contractility

(cell rounding)

EB1/APC

Microtubule growth and stabilization

Spread, control

cell

Contracted cell with

constitutively active RhoA

Note: These images have been generated through a 90 degree vertical projection of z-series images

Y27632 treatment

• Y27632 inhibits Rho kinase which causes actin-myosin contractility leading to rounded cell shape.

• Different concentrations of Y27632 used 0μM, 1.0 μM, 1.5 μM, 2.0 μM 2.5 μM, 5.0 μM, 10.0 μM

• High concentrations of Y27632 allow the cell shape to return to normal

• Goal: What is the point where cell shape remains contracted but the spindle orientation returns to normal? – Will show that the spindle misorientation is not a

direct effect of contracted shape caused by RhoA, and thus, is caused by a different aspect of the RhoA signaling pathway.