Inhibition of Neurite Outgrowth by Stably Expressed Go alpha in F11 Cells

Ghil, Sung Ho; Suh-Kim, Hae Young

Abstract

Heterotrimeric G proteins mediate signals generated by neurotransmitters and hormones. Among G proteins, Go is found in a large quantity in brain and growth cone membranes of neurons. In spite of its abundance in neurons, the role of Go is not fully understood. In the previous study, we showed that transient expression of the alpha subunit of Go (alpha o) modulated neurite outgrowth in F11 cells. It is possible that transient transfection may cause transient accumulation of the protein, which itself may alter differentiation process in non-specific manner. In this study, we determined that modulation of neurite outgrowth by alpha o was specific by evaluating the effect of alpha o in stably transformed F11 cells. F11 cells stably expressing the wild type alpha o (alphao(wt)) and a constitutively active form of alpha o (alpha oQ205L) were established. In normal F11 cells and alpha o-stable cell lines, the neurite length was measured in the presence of dibutyryl cAMP. In normal F11 cells, the average length of neurites was 57.9+/-7.0 microgram. In alpha o(wt)- and alpha o(Q205L)-expressing cells, the average length were 34.4+/-5.1 microgram 30.5+/-3.6 microgram, respectively. Thus, stable expression of alpha o(wt) and alpha o(Q205L) caused a decrease in neurite outgrowth by 40.6%, 47.3% respectively. This result indicates that modulation of neurite by alpha o was specific to the function of alpha o but not due to accumulation of exogenous proteins.