Human TPST1 transmembrane domain triggers enzyme dimerisation and localisation to the Golgi compartment.
TPST1 is a human tyrosylprotein sulfotransferase that uses 3'phosphoadenosine-5'phosphosulfate (PAPS) to transfer the sulfate moiety to proteins predominantly designated for secretion. To achieve a general understanding of the cellular role of human tyrosine-directed sulfotransferases, we investigated targeting, structure and posttranslational modification of TPST1. Golgi localisation of the enzyme in COS-7 and HeLa cells was visualised by fluorescence imaging techniques. PNGase treatment and mutational studies determined that TPST1 bears N-linked glycosyl residues exclusively at position Asn60 and Asn262. By alanine mutation of these asparagine residues, we could determine that the N-linked oligosaccharides do not have an influence on Golgi retention of TPST1. In concert with N and C-terminal flanking residues, the transmembrane domain of TPST1 was determined to act in targeting and retention of the enzyme to the trans-Golgi compartment. This domain exhibits a pronounced secondary structure in a lipid environment. Further in vivo FRET studies using the transmembrane domain suggest that the human tyrosylprotein sulfotransferase may be functional as homodimer/oligomer in the trans-Golgi compartment.
Goettsch
Sandra
S
Department of Structural and Medicinal Biochemistry, University of Duisburg-Essen and Centre for Medicinal Biotechnology, Universitätsstr. 2-5, 45117 Essen, Germany.
Badea
Rodica A
RA
Mueller
Jonathan W
JW
Wotzlaw
Christoph
C
Schoelermann
Beate
B
Schulz
Lars
L
Rabiller
Matthias
M
Bayer
Peter
P
Hartmann-Fatu
Cristina
C
D000595:Amino Acid Sequence; D000818:Animals; D001216:Asparagine / Q000235:genetics / Q000378:metabolism; D001324:Autoantigens / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D019281:Dimerization; D031541:Fluorescence Resonance Energy Transfer; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism*; D000077614:Golgi Matrix Proteins; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009844:Oligosaccharides / Q000378:metabolism; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D015238:Sulfotransferases / Q000235:genetics / Q000502:physiology*
D001324:Autoantigens; D000077614:Golgi Matrix Proteins; C450721:Golgi complex autoantigen, 97-kDa; D009844:Oligosaccharides; D001216:Asparagine; D015238:Sulfotransferases; C039079:protein-tyrosine sulfotransferase