Characterization of a novel phosphatidylinositol 3-phosphate-binding protein containing two FYVE fingers in tandem that is targeted to the Golgi.
We have identified a novel protein of predicted molecular mass 40 kDa that contains two FYVE domains in tandem and has therefore been named TAFF1 (TAndem FYVE Fingers-1). The protein is expressed predominantly in heart and binds to PtdIns3P specifically, even though the FYVE domains in TAFF1 lacks the first Arg of the consensus sequence R(K/R)HHCR, critical for the PtdIns3P binding of other FYVE domains identified so far. The first Arg is replaced by a Thr and Ser in the N-terminal and C-terminal FYVE domains of TAFF1 respectively. Mutational analysis indicates that both FYVE domains are required for high affinity binding to PtdIns3P. Cell localization studies using a green fluorescent protein fusion show that TAFF1 is localized to the Golgi, and that the Golgi targeting sequence is located within the N-terminal 187 residues and not in either FYVE domain.
MRC Protein Phosphorylation Unit, MSI/WTB Complex, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, U.K. pcheung1@biochem.dundee.ac.uk
P C
PC
Cheung
L
L
Trinkle-Mulcahy
P
P
Cohen
J M
JM
Lucocq
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; D018076:DNA, Complementary; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; C426003:ZFYVE1 protein, human; D049452:Green Fluorescent Proteins