Comparing two-component signal transduction systems and phosphorelay systems, . Multiple Choice the two processes differ only in that phosphorelay systems are more widespread than two-component signal transduction systems two-component signal transduction systems mediate the transfer of a single phosphoryl group from a sensor kinase to a response regulator, whereas phosphorelay systems transfer multiple phosphoryl groups between a series of proteins two-component signal transduction systems mediate the transfer of multiple phosphoryl groups between a variety of sensor kinases, whereas phosphorelay systems transfer a single phosphoryl group to a response regulator phosphorelay systems mediate the transfer of a single phosphoryl group from a sensor kinase to a response regulator, whereas two-component signal transduction systems transfer multiple phosphoryl groups between a series of proteins