Differential requirements for clathrin in receptor-mediated endocytosis and maintenance of synaptic vesicle pools.
Clathrin is a coat protein involved in vesicle budding from several membrane-bound compartments within the cell. Here we present an analysis of a temperature-sensitive (ts) mutant of clathrin heavy chain (CHC) in a multicellular animal. As expected Caenorhabditis elegans chc-1(b1025ts) mutant animals are defective in receptor-mediated endocytosis and arrest development soon after being shifted to the restrictive temperature. Steady-state clathrin levels in these mutants are reduced by more than 95% at all temperatures. Hub interactions and membrane associations are lost at the restrictive temperature. chc-1(b1025ts) animals become paralyzed within minutes of exposure to the restrictive temperature because of a defect in the nervous system. Surprisingly synaptic vesicle number is not reduced in chc-1(b1025ts) animals. Consistent with the normal number of vesicles, postsynaptic miniature currents occur at normal frequencies. Taken together, these results indicate that a high level of CHC activity is required for receptor-mediated endocytosis in nonneuronal cells but is largely dispensable for maintenance of synaptic vesicle pools.
Sato
Ken
K
Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan. ken@showa.gunma-u.ac.jp
Ernstrom
Glen G
GG
Watanabe
Shigeki
S
Weimer
Robby M
RM
Chen
Chih-Hsiung
CH
Sato
Miyuki
M
Siddiqui
Ayesha
A
Jorgensen
Erik M
EM
Grant
Barth D
BD
D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D033922:Clathrin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis; D009154:Mutation / Q000235:genetics; D009469:Neuromuscular Junction / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000378:metabolism / Q000648:ultrastructure; D011956:Receptors, Cell Surface / Q000378:metabolism*; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000378:metabolism* / Q000648:ultrastructure
D029742:Caenorhabditis elegans Proteins; D011956:Receptors, Cell Surface; C535031:chc-1 protein, C elegans; D033922:Clathrin Heavy Chains