Pak1 kinase plays a role in promoting endocytosis. (A) Schematic depicting our hypothesis that Pak1 activity promotes its own removal through endocytosis. (B) Montages of Fim1-mEGFP labeled endocytic patches at growing ends of interphase pak1⁺ and pak1-ts cells (scale bars = 800 nm; frame rates = 1 s per frame [SPF]). (C) Quantification for lifetimes of Fim1-mEGFP labeled endocytic patches in pak1⁺ and pak1-ts (n = 15 endocytic patches per experiment, N = 3 experiments). (D) Quantification of Fim1-mEGFP labeled endocytic patch internalization into the cell interior from the plasma membrane in pak1-ts mutants compared to pak1⁺ cells (n = 20 endocytic patches per genotype per experiment, N = 3 experiments). (E) Quantification of failed endocytic events in pak1⁺ cells compared to pak1-ts. Failed events do not internalize beyond 350 nm from the plasma membrane (n = 20 endocytic patches per genotype per experiment, N = 3 experiments). Symbol colors in graphs = distinct experiments. Solid symbols = means of experiments. n.s., not significant; P value, **<0.01, Student’s t test.