Overlapping functions of different dynamin isoforms in clathrin-dependent and -independent endocytosis in pancreatic beta cells.
Previously, we identified a clathrin-dependent slow endocytosis and a clathrin-independent fast endocytosis in pancreatic beta cells, both triggered by elevated cytoplasmic Ca(2+) concentration. In the current study, we attempted to explore the roles of different dynamin isoforms in these endocytotic processes. We first confirmed the existence of both neuron-specific dynamin 1 and ubiquitous dynamin 2 in INS-1 cells using both quantitative RT-PCR and Western blot experiments. By specifically knocking down the endogenous level of either dynamin isoform from INS-1 cells, we showed that dynamin 1 and dynamin 2 simultaneously participate in the clathrin-independent and -dependent membrane retrieval in pancreatic beta cells. Transferrin internalization was also inhibited in cells with knock down of both dynamin 1 and dynamin 2. Based on these results, we argue that different dynamin isoforms play overlapping roles in different types of endocytosis.
Lu
Jingze
J
National Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Science, Datun Road 15#, Beijing 100101, PR China.
He
Zixuan
Z
Fan
Junmei
J
Xu
Pingyong
P
Chen
Liangyi
L
D000818:Animals; D045744:Cell Line, Tumor; D002966:Clathrin / Q000235:genetics / Q000378:metabolism*; D034284:Dynamin I / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D034285:Dynamin II / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis; D006801:Humans; D050417:Insulin-Secreting Cells / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D020033:Protein Isoforms / Q000032:analysis / Q000235:genetics / Q000378:metabolism
D002966:Clathrin; D020033:Protein Isoforms; D034284:Dynamin I; D034285:Dynamin II