Clathrin anchors deubiquitinating enzymes, AMSH and AMSH-like protein, on early endosomes.
Endosomal sorting of ubiquitinated membrane proteins for trafficking to lysosomes is executed by a complex of two ubiquitin-binding proteins, Hrs and STAM, that localizes on a microdomain of early endosomes with a flat clathrin coat. AMSH is a deubiquitinating enzyme that interacts with STAM and is implicated in the down-regulation of epidermal growth factor receptor. AMSH has a close homolog, AMSH-like protein (AMSH-LP). Here we show that AMSH-LP is also a deubiquitinating enzyme that acts on early endosomes. We further show that AMSH and AMSH-LP bind to the terminal domain of clathrin heavy chain via a novel clathrin-binding site conserved between these proteins. Exogenously expressed AMSH and AMSH-LP co-localized with clathrin on early endosomes. However, deletion of the clathrin-binding site from the proteins, as well as RNA interference-mediated depletion of clathrin heavy chain, resulted in a failure of AMSH and AMSH-LP to localize on endosomes. In contrast, a mutant of AMSH that lacks the ability to bind STAM localized normally on endosomes. We suggest that AMSH and AMSH-LP are anchored on the early endosomal membrane via interaction with the clathrin coat.
Nakamura
Michihiko
M
Department of Biological Sciences, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
Tanaka
Nobuyuki
N
Kitamura
Naomi
N
Komada
Masayuki
M
D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002966:Clathrin / Q000378:metabolism*; D033922:Clathrin Heavy Chains / Q000235:genetics / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport; D011992:Endosomes / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010447:Peptide Hydrolases; D034622:RNA Interference; D043222:Ubiquitin Thiolesterase; D014452:Ubiquitins / Q000378:metabolism
D002352:Carrier Proteins; D002966:Clathrin; D056827:Endosomal Sorting Complexes Required for Transport; C486696:STAMBP protein, human; D014452:Ubiquitins; D033922:Clathrin Heavy Chains; D010450:Endopeptidases; D010447:Peptide Hydrolases; C476302:STAMBPL1 protein, human; D043222:Ubiquitin Thiolesterase