Molecular Cloning and Characterization of a Novel 3′-Phosphoadenosine 5′-Phosphosulfate Transporter, PAPST2

Abstract

Sulfation is an important posttranslational modification associated with a variety of molecules. It requires the involvement of the high energy form of the universal sulfate donor, 3-phosphoadenosine 5-phosphosulfate (PAPS). Recently, we identified a PAPS transporter gene in both humans and Drosophila. Although human colonic epithelial tissues express many sulfated glycoconjugates, PAPST1 expression in the colon is trace. In the present study, we identified a novel human PAPS transporter gene that is closely related to human PAPST1. This gene, called PAPST2, is predominantly expressed in human colon tissues. The PAPST2 protein is localized on the Golgi apparatus in a manner similar to the PAPST1 protein. By using yeast expression studies, PAPST2 protein was shown to have PAPS transport activity with an apparent K m value of 2.2 M, which is comparable with that of PAPST1 (0.8 M). Overexpression of either the PAPST1 or PAPST2 gene increased PAPS transport activity in human colon cancer HCT116 cells. The RNA interference of the PAPST2 gene in the HCT116 cells significantly reduced the reactivity of G72 antibody directed against the sialyl 6-sulfo N-acetyllactosamine epitope and total sulfate incorporation into cellular proteins. These findings indicate that PAPST2 is a PAPS transporter gene involved in the synthesis of sulfated glycoconjugates in the colon.

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

“…In plants and animals, these reactions occur both in the cytosol and the Golgi lumen. Animal Golgi-resident PAPS transporters mediating the import of PAPS synthesized in the cytosol have been identified in Drosophila melanogaster (SLALOM; Lüders et al, 2003), human (PAPST1 and PAPST2; Kamiyama et al, 2003Kamiyama et al, , 2006, zebra fish (PAPST1; Clément et al, 2008), and Caenorhabditis elegans (PST-1; Bhattacharya et al, 2009). These transporters are involved in the sulfation of glycoconjugates, such as glycans, and the resulting sulfated molecules take part in the regulation of various developmental and intercellular signaling processes (Bishop et al, 2007).…”

SLC35B2 Expression is Associated with a Poor Prognosis of Invasive Ductal Breast Carcinoma

“…In Drosophila, these PAPS transporters are required for the sulfation of cellular proteins and normal development. In humans, both PAPST1 (SLC35B2) and PAPST2 (SLC35B3) are necessary for the sulfation of the 6-sulfolactosamine epitope in a human colorectal carcinoma cell line (Huopaniemi et al, 2004;Kamiyama et al, 2006). The SLC35B2 gene also plays an important role in cancer-cell proliferation, by controlling their sulfation status as part of a desmoplastic reaction to support cancer growth in colorectal cancers (Kamiyama et al, 2011).…”

Identification of a retroviral receptor used by an Envelope protein derived by peptide library screening

“…Of interest is the subcellular localization of the known SLC35 family members that predominate in the lumen of the endoplasmic reticulum and the Golgi (38,41). For the SLC35F2 protein to function as a viral receptor, the primary contact point is assumed to be on the cell surface.…”

“…The SLC35A1 transports CMP-Sia, SLC35A2 transports UDP-Gal (38,39), SLC35A3 transports UDP-GlcNAc (38,39), SLC35C1 encodes a GDP-Fuc transporter (39), and SLC35D1 transports UDP-GlcA/UDP-GalNac (40). SLC35B3 encodes a 3Ј phosphoadenosine 5Ј-phosphosulfate (PAPS) transporter, involved in formation of sulfated proteoglycans and glycoproteins (41). There are five members of the SLC35 subfamily F (F1-F5); however, no function has been identified for any of the members.…”