Fig. 1. Different types of endocytosis. Four main types of endocytosis are shown (which might be an over-simplification). Caveolar endocytosis and clathrin-mediated endocytosis both require the GTPase dynamin 1, whereas other types of endocytosis do not. As implied by the figure, it is not clear how many different types of dynamin-independent pinocytic or macropinocytic mechanisms there are (discussed in the text).