Gtpase activity is important in the regulation of signal transduction because it

It responses when cell surface receptors are activated especially trans membrane receptors such as taste, smell and vision.

Explanation:

GTPases are a large group of hydrolase enzymes that link to the nucleotide guanosime triphosphase and hydrolyze it to guamosine diphosphate.

Signal transduction is the process whereby a chemical or physical signal is transmitted using a cell as series of molecular events or activities mostly protein Phosphorylation catalyzed by protein kinases which are finally resulting in a cellular response. Receptors are seen as proteins which can sense stimuli even though most times, sensors are used.