Identification of tyrosylprotein sulfotransferase in Arabidopsis

Abstract

Tyrosine sulfation is a posttranslational modification common in peptides and proteins synthesized by the secretory pathway in most eukaryotes. In plants, this modification is critical for the biological activities of a subset of peptide hormones such as PSK and PSY1. In animals, tyrosine sulfation is catalyzed by Golgilocalized type II transmembrane proteins called tyrosylprotein sulfotransferases (TPSTs). However, no orthologs of animal TPST genes have been found in plants, suggesting that plants have evolved plant-specific TPSTs structurally distinct from their animal counterparts. To investigate the mechanisms of tyrosine sulfation in plants, we purified TPST activity from microsomal fractions of Arabidopsis MM2d cells, and identified a 62-kDa protein that specifically interacts with the sulfation motif of PSY1 precursor peptide. This protein is a 500-aa type I transmembrane protein that shows no sequence similarity to animal TPSTs. A recombinant version of this protein expressed in yeast catalyzed tyrosine sulfation of both PSY1 and PSK precursor polypeptide in vitro, indicating that the newly identified protein is indeed an Arabidopsis (At)TPST. AtTPST is expressed throughout the plant body, and the highest levels of expression are in the root apical meristem. A loss-of-function mutant of AtTPST displayed a marked dwarf phenotype accompanied by stunted roots, pale green leaves, reduction in higher order veins, early senescence, and a reduced number of flowers and siliques. Our results indicate that plants and animals independently acquired tyrosine sulfation enzymes through convergent evolution.Golgi ͉ peptide hormone ͉ posttranslational modification ͉ tyrosine sulfation ͉ sulfated tyrosine T yrosine sulfation is a common posttranslational modification found in peptides and proteins synthesized through the secretory pathway of most eukaryotes, including higher plants. This modification is thought to be mediated by an enzyme, tyrosylprotein sulfotransferase (TPST), which catalyzes the transfer of sulfate from 3Ј-phosphoadenosine 5Ј-phosphosulfate (PAPS) to the phenolic group of tyrosine (1). To date, 2 tyrosine sulfated peptide hormones, PSK and PSY1, have been found in plants. PSK is a 5-aa secreted peptide containing 2 sulfated tyrosines, and was initially identified as a growth-promoting factor involved in the ''density effect'' in plant cell cultures (2). PSK is recognized by a membrane-localized leucine-rich repeat (LRR) receptor kinase, PSKR1, and promotes cellular proliferation at nanomolar concentrations (3). Disruption of PSKR1 and its 2 homologs in Arabidopsis causes pleiotropic growth defects such as short roots, smaller leaves, and early senescence (4). PSY1 is an 18-aa secreted glycopeptide containing 1 sulfated tyrosine, and was identified by exhaustive analysis of tyrosine sulfated peptides in plant cell culture media (4). PSY1 also promotes cellular proliferation at nanomolar concentrations. There is evidence that one PSKR1 homolog is involved in the recognition of PSY1 (4). Both PSK and PSY...

The Arabidopsis Thylakoid ADP/ATP Carrier TAAC Has an Additional Role in Supplying Plastidic Phosphoadenosine 5′-Phosphosulfate to the Cytosol

“…These transcription factors were shown to activate the PAPST1 promoter, again indicating a link between GS biosynthesis and PAPS transport. Similar to PAPST1, genes encoding PSK, PSY, and RGF peptide precursors (Kutschmar et al, 2009;Matsuzaki et al, 2010;Zhou et al, 2010;Stührwohldt et al, 2011) as well as the TPST gene (Komori et al, 2009), all involved in the sulfation/activation of these hormonelike peptides, are present in meristematic tissues. In addition, Levels of thiols were determined as described in Methods.…”

“…Posttranslational Tyr sulfation occurs also in small secreted peptides that act as signal molecules regulating growth, development, and differentiation in multicellular organisms. Tyrosylprotein sulfotransferases mediate the sulfate transfer from PAPS to Tyr residues in propeptides that are finally processed to the active forms, small secreted peptides (Komori et al, 2009). A prominent example is the disulfated pentapeptide phytosulfokine PSK-a.…”

“…Defects in PAPS synthase cause growth disorders, spondyloepimetaphyseal dysplasia in humans (Faiyaz ul Haque et al, 1998), and brachymorphism in mice (Kurima et al, 1998). In Arabidopsis thaliana, sulfation is an important step for the production of sulfated secondary metabolites, such as glucosinolates and sulfoflavonoids, or of sulfated peptides that have regulatory functions (Yang et al, 1999(Yang et al, , 2001Matsubayashi et al, 2006;Komori et al, 2009;Kutschmar et al, 2009;Matsuzaki et al, 2010;Zhou et al, 2010;Stührwohldt et al, 2011). Glucosinolates (GS) are secondary metabolites involved in plant biotic interactions.…”

RGF1 INSENSITIVE 1 to 5, a group of LRR receptor-like kinases, are essential for the perception of root meristem growth factor 1 in Arabidopsis thaliana

“…The active peptides contain about 13 amino acids with an Asp-Tyr signature critical for tyrosine sulfation, which is required for the activity of RGFs [25]. There is only one gene encoding tyrosylprotein sulfotransferase (TPST) in Arabidopsis genome [29]. tpst-1 mutant shows a short root phenotype with significantly reduced meristematic activity [25,30].…”

Phytosulfokine Regulates Growth in Arabidopsis through a Response Module at the Plasma Membrane That Includes CYCLIC NUCLEOTIDE-GATED CHANNEL17, H+-ATPase, and BAK1

“…Phytosulfokine (PSK) is a pentapeptide of the sequence Tyr-Ile-Tyr-ThrGln with a sulfate group attached to each of the two tyrosine residues (Matsubayashi and Sakagami, 1996;Sauter, 2015). Sulfation occurs in the trans-Golgi and is catalyzed by a tyrosylprotein sulfotransferase during passage of the proprotein through the secretory pathway (Komori et al, 2009). Partial proteolytic processing of the Arabidopsis thaliana PSK4 proprotein but not of other proproteins was shown to occur in the apoplast by the subtilase SBT1.1 (Srivastava et al, 2008).…”