Regulus marked the summer solstice and was thus associated with the innundation, as seen in the iconography of Denderah for example. The sun was rising around the postion were Sirius rose at the time of the winter solstice, it's helical return at the summer solstice in effect suggesting some sort of balance and harmony along the length of the ecliptic path between the solstice points, but this was a secondary factor compared to the role of Regulus.
You will find that Arcturus was concerned with the viticulture season, and Spica with the grain harvest, throughout the ancient Mediterranean world, including Egypt.
Morph.