Synaptojanin 1: localization on coated endocytic intermediates in nerve terminals and interaction of its 170 kDa isoform with Eps15.
Synaptojanin 1 is an inositol 5-phosphatase with a putative role in clathrin-mediated endocytosis. Goal of this study was to provide new evidence for this hypothesis. We show that synaptojanin 1 is concentrated at clathrin-coated endocytic intermediates in nerve terminals. Furthermore, we report that synaptojanin-170, an alternatively spliced isoform of synaptojanin 1, binds Eps15, a clathrin coat-associated protein. Binding is mediated by the COOH-terminal region of synaptojanin-170 which we show here to be poorly conserved from rat to humans, but to contain in both species three asparagine-proline-phenylalanine (NPF) repeats. This motif has been found to be the core of the binding site for the EH domains of Eps15. Together with previous data, our results suggest that synaptojanin 1 can be recruited to clathrin-coated pits via a multiplicity of interactions.
Haffner
C
C
Department of Cell Biology and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA.
Takei
K
K
Chen
H
H
Ringstad
N
N
Hudson
A
A
Butler
M H
MH
Salcini
A E
AE
Di Fiore
P P
PP
De Camilli
P
P
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002966:Clathrin; D004705:Endocytosis; D006801:Humans; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009411:Nerve Endings / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D016415:Sequence Alignment; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; D002966:Clathrin; C486206:EPS15 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; C097702:synaptojanin; D010744:Phosphoric Monoester Hydrolases