Expression and protein-binding studies of the EEN gene family, new interacting partners for dynamin, synaptojanin and huntingtin proteins.
EEN, identified initially as a fusion partner to the mixed-lineage leukaemia gene in human leukaemia, and its related members, EEN-B1 and EEN-B2, have recently been shown to interact with two endocytic molecules, dynamin and synaptojanin, as well as with the huntingtin protein. In the present study, we show that the expression of the EEN gene-family members is differentially regulated. Multiple-spliced variants were identified for EEN-B2. In the brain, EEN-B1 and EEN-B2 mRNA are preferentially expressed in the cerebellar Purkinje and granule cells, dentate gyrus cells, hippocampal pyramidal neurons and cerebral granule cells. The expression patterns of EEN-B1 and EEN-B2 mRNA in the brain overlap with those of dynamin-I/III, synaptojanin-I and huntingtin, whereas the ubiquitous expression of EEN is consistent with that of dynamin-II. In testes, members of the EEN family are co-expressed with testis-type dynamin and huntingtin in Sertoli cells and germ cells respectively. Our results on the overlapping expression patterns are consistent with the proposed interaction of EEN family members with dynamin, synaptojanin and huntingtin protein in vivo. Although all three EEN family members bind to dynamin and synaptojanin, EEN-B1 has the highest affinity for binding, followed by EEN and EEN-B2. We also demonstrate that amphiphysin, a major synaptojanin-binding protein in brain, can compete with the EEN family for binding to synaptojanin and dynamin. We propose that recruitment of the EEN family by dynamin/synaptojanin to clathrin-coated pits can be regulated by amphiphysin.
So
C W
CW
Department of Pathology, The University of Hong Kong, Hong Kong, Peoples' Republic of China. cwso@stanford.edu
Sham
M H
MH
Chew
S L
SL
Cheung
N
N
So
C K
CK
Chung
S K
SK
Caldas
C
C
Wiedemann
L M
LM
Chan
L C
LC
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D003001:Cloning, Molecular; D034284:Dynamin I; D034286:Dynamin III; D034281:Dynamins; D005314:Embryonic and Fetal Development; D004791:Enzyme Inhibitors / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D014644:Genetic Variation; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014158:Transcription, Genetic
D004791:Enzyme Inhibitors; C086055:HTT protein, human; C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; C105159:SH3GL1 protein, human; C097702:synaptojanin; D010744:Phosphoric Monoester Hydrolases; D034284:Dynamin I; D020558:GTP Phosphohydrolases; D034286:Dynamin III; D034281:Dynamins