This book provides the most updated information of how membrane lipids mediate protein signaling from studies carried out in animal and plant cells. Also, there are some chapters that go beyond and expand these studies of protein-lipid interactions at the structural level. The book begins with a literature review from investigations associated to sphingolipids, followed by studies that describe the role of phosphoinositides in signaling and closing with the function of other key lipids in signaling at the plasma membrane and intracellular organelles.