Question

Which of the outcomes could potentially result if a mutation in the gene encoding the Gα subunit eliminates its GTPase activity? Choose three outcomes. Gα would be activated for an extended period. The concentration of cAMP in the cell would be continuously elevated. Gα would be ineffective as a signal molecule (that is, it could not activate other proteins). The signaling pathway could be activated for an extended period, possibly resulting in undesirable cell proliferation. The rate of GTP hydrolysis would increase. The cell would be unresponsive to molecules that act via cAMP .

Answer 1

The prime function of the GTPase activity of the G-alpha protein is to perform the hydrolysis of the attached guanosine triphosphate or GTP. Upon combination with the GTP, the G-alpha protein becomes activated, and when hydrolysis of GTP takes place to guanosine diphosphate or GDP, the G-alpha subunit becomes inactivated.

Therefore, the activity of the GTPase provides the G protein-coupled signaling mechanism's regulation. In case, if the mutation takes place within the gene encrypting the G-alpha subunit, then the inhibition of GTPase activity occurs, which would eventually result in the following outcomes:

1. The stimulation of the signaling pathway may take place for a prolonged time duration, eventually causing an unwanted differentiation of the cell.

2. There would be a spontaneous enhancement in the concentration of cyclic-AMP within the cell.

3. The activation of the G-alpha subunit would take place for a prolonged time duration.