Glycobiology Advance Access originally published online on March 6, 2003
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Glycobiology, 2003, Vol. 13, No. 5 11G-12G
© 2003 Oxford University Press
GLYCO-FORUM SECTION |
Letter to the Glyco-Forum
Shooting HARE
2 Department of Experimental Pathology, University of Tromsø, Mh Building, NO-9037 Tromsø, Norway
3 Department of Medical Biochemistry and Microbiology (imbim), University of Uppsala, BMC Box 582, SE-75123 Uppsala, Sweden
4 Department of Dermatology, University Medical Center Mannheim, Ruprecht Karls University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68135 Mannheim, Germany
Received on January 31, 2003; accepted on February 14, 2003
Key words: endocytic hyaluronan receptor / HARE / scavenger receptor / sinusoidal liver endothelial cells / stabilin
We are writing to raise an issue regarding the article by Zhou et al. (2003)
, "Purification and molecular identification of the human hyaluronan receptor for endocytosis (HARE)," which is published in this issue of Glycobiology and which first appeared electronically in Glycobiology Advance Access on December 17, 2002 (DOI: 10.1093/ glycob/cwg029). In this article, Zhou et al. (2003) misrepresent or ignore our work toward the purification and cloning of the sinusoidal liver endothelial cell (sLEC) endocytic hyaluronan (HA) receptor, a protein they call HARE.
To provide some background to this issue, we will briefly summarize our work on this receptor. Two Scandinavian groups, led by Johansson (Uppsala) and Smedsrod (Tromsø), respectively, purified the sLEC HA receptor on HA-affinity columns and developed specific antibodies able to inhibit the endocytosis of HA by sLEC. Because of the similarities between stabilin-1 (initially identified by Goerdt et al. 1991; accession numbers AJ275213 and AF290914) and the HA receptor on sLEC, the Scandinavian groups established a collaboration with Goerdt's group in Germany. Together we subsequently cloned the human and mouse forms of the receptor (accession numbers AJ295695 and AF364951), based on the peptide information derived from purified sLEC HA receptor (Politz et al., 2002). The sLEC HA receptor proved to have 41% homology with stabilin-1 and was thus named stabilin-2. The HUGO and Mouse Genome Nomenclature Committees have since approved the gene names stabilin-1 and stabilin-2.
Zhou et al. (2003) represent our above work as follows:
HARE and the BAB15793 sequence, which has recently been extended by several other submissions to the database, may be derived from a large protein originally designated Stabilin-2, deposited as a sequence of unknown function (Politz et al., 2002
Stating that stabilin-2 had an "unknown function" is incorrect because in Politz et al. (2002) it is clearly stated throughout that stabilin-2 codes for the endocytic HA receptor on sLEC. In addition, we showed that the endocytic function is not limited to HA because stabilin-2 was also demonstrated to be responsible for the clearance of some scavenger receptor ligands but not collagen (McCourt et al., 1999).
Furthermore, to state that "the Stabilin-2 sequence was obtained from a soluble protein, which was isolated from whole liver extracts" as the article does, is a misrepresentation of our sLEC HA receptor purification work, as published by McCourt et al. (1999) and Politz et al. (2002). Zhou et al. (2003) have also elected not to cite McCourt et al. (1999), in which we give a full description of our sLEC HA receptor (stabilin-2) characterization studies.
Finally, given that we have purified and cloned the sLEC HA receptor, it is also incorrect for Zhou et al. (2003) to state that they "have identified the first function for a member of this protein family." We were in fact the first to submit sequence data for the human form (accession number AJ295695, submission date July 27, 2000) and first to publish the function of this cloned protein in February 2002 in Politz et al. (2002). The cDNA coding for rat "HARE" (accession number AY007370, submission date August 25, 2000) at 4.7 kb, as described in August 2002 (Zhou et al. 2002), is in fact only a partial form of stabilin-2 (8.3 kb).
In conclusion, Zhou et al. (2003) have presented an incomplete account of current work in this field. We hope therefore that this letter to the Glyco-Forum will provide the readership with a more comprehensive perspective regarding the characterization of the endocytic HA receptor on sLEC, namely stabilin-2.
1 To whom correspondence should be addressed; e-mail: baards{at}fagmed.uit.no 
Abbreviations
HA, hyaluronan; HARE, hyaluronan receptor for endocytosis; sLEC, sinusoidal liver endothelial cells.
References
Goerdt, S., Walsh, L.J., Murphy, G.F., and Pober, J.S. (1991) Identification of a novel high molecular weight protein preferentially expressed by sinusoidal endothelial cells in normal human tissues. J. Cell. Biol., 113, 1425–1437.
McCourt, P.A., Smedsrod, B.H., Melkko, J., and Johansson, S. (1999) Characterization of a hyaluronan receptor on rat sinusoidal liver endothelial cells and its functional relationship to scavenger receptors. Hepatology, 30, 1276–1286.[CrossRef][Web of Science][Medline]
Politz, O., Gratchev, A., McCourt, P.A., Schledzewski, K., Guillot, P., Johansson, S., Svineng, G., Franke, P., Kannicht, C., Kzhyshkowska, J., and others. (2002), Stabilin-1 and -2 constitute a novel family of fasciclin-like hyaluronan receptor homologues. Biochem. J., 362, 155–164.[CrossRef][Web of Science][Medline]
Zhou, B., Weigel, J.A., Saxena, A., and Weigel, P.H. (2002) Molecular cloning and functional expression of the rat 175-kDa hyaluronan receptor for endocytosis. Mol. Biol. Cell, 13, 2853–2868.
Zhou, B., McGary, C.T., Weigel, J.A., Saxena, A., and Weigel, P.H. (2003) Purification and molecular identification of the human hyaluronan receptor for endocytosis (HARE). Glycobiology, 13, 339–349.
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