Table 1.

Examples of Hulks and Deadpools.

Hulks	Deadpools	Commentary
tZ, iP	cZ aromatic cytokinins	While tZ and iP induce large changes in plant physiology, cZ and aromatic cytokinins are “slow” with weak CK activity, but they are resistant and thus persistent.
AtIPT3	AtIPT5, SlIPT3 and PpIPT5a tRNA IPTs	AtIPT3 is the main enzyme synthesising CKs with spatio-temporally focused production; on the other hand, IPT5 orthologues are expressed widely but they have only low activity, thus producing small less focused amounts of CKs. tRNA IPTs usually exert wide expression and they produce the Deadpool cZ.
receptors on PM	receptors on ER	PM-localised receptors may perceive the Hulk CKs tZ and iP with very high activity. To diminish Hulk signalling when Hulk CKs are not present, AHK4 also possesses a phosphatase activity. On the other hand, ER-localised receptors perceive autocrine Deadpool signals.
LOGs AtLOG7	two-step activation AtLOG8	LOGs activate CKs (almost) in a single step from biosynthesis products specifically in regions of high cell division activities, while the two-step activation functions throughout the plant body at low speed. Among LOGs, one can distinguish AtLOG7 with high activity and expression focused to high activity hotspots and AtLOG8 with minimal activity but expression throughout the plant.