PDF Chapter 2: Exocytosis and endocytosis - UniversitĂ  degli studi di Trieste Most of the plasma membrane components (proteins and lipid) that are endocytosed are continually returned to the cell surface by exocytosis (up to 50% / hr). Maturation of early endosome Maturation from early endosomes (EE) to late endosomes (LE). EEs accumulate cargo and support recycling to the plasma membrane.