Sulfogalactolipid binding protein SLIP 1: A conserved function for a conserved protein

Law, Helen K. W.; Itkonnen, O.; Lingwood, Clifford A.

doi:10.1002/jcp.1041370310

Cited by 36 publications

(33 citation statements)

References 21 publications

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“…It is likely that a similar model would apply to VT1. Other examples of specific protein glycolipid interactions include several proteins that show affinity for sulfatide (31) and our own work on sulfogalactolipid binding proteins in the testis (32).…”

Section: Resultsmentioning

confidence: 99%

Induction of verotoxin sensitivity in receptor-deficient cell lines using the receptor glycolipid globotriosylceramide.

Waddell

Cohen

Lingwood

1990

Proc. Natl. Acad. Sci. U.S.A.

114

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Verotoxin 1 is an Escherichia coli-derived subunit toxin that specifically binds to the glycolipid globotriosylceramide and is cytotoxic for cells that contain this plasma membrane glycolipid. Glycolipid incorporation experiments have now been performed using human lymphoid cells of the B lineage that lack this receptor, to conclusively demonstrate that globotriosylceramide alone is a functional receptor for this toxin. Globotriosylceramide incorporated into the membrane of toxin-resistant cells provides intracellular access to verotoxin by receptor-mediated endocytosis. Protein synthesis is then inhibited and globotriosylceramide-containing cells are killed.Verotoxin (VT) is an Escherichia coli elaborated subunit toxin (1, 2) highly homologous with Shiga toxin (from Shigella dysenteriae type 1) and, therefore, also referred to as Shiga-like toxin or SLT (2, 3). At least two variants of VT have been described, termed VT1 and VT2 (4) [or SLTI and SLTII (5)]. Research interest has focused on these toxins since they have been strongly implicated as the causative agent of the renal damage seen in the hemolytic uremic syndrome (HUS) (6, 7). Evidence for the presence of VT has been found in nearly 90% of patients with HUS in this hospital over the last 5 years.A4 HUS is usually preceded by hemorrhagic colitis (6) and similar gastrointestinal symptoms are obtained when purified VT is administered to rabbits (8).Most cells are entirely resistant to VT cytopathology. HeLa (9), Vero (6), and Daudi human lymphoma cells (10) have, however, been shown to be highly susceptible. It is possible that the basis of such differential sensitivity resides at the level of the cell surface toxin receptor.VT1 (11), VT2 (12), and Shiga toxin (9, 13) have been shown to bind specifically to the neutral glycolipid globotriosylceramide (galactose al-4galactose,81-4glucosylcera-mide; Gb3). We have proposed (10) MATERIALS AND METHODS Gb3 and globotetraosylceramide (Gb4) were purified from human renal tissue by a modification of the procedure as described by Strasberg et al. (14). The chloroform/methanol tissue extract was first applied on a Bio-Sil A (Bio-Rad) silica column in chloroform. The column was extensively washed with chloroform and neutral glycolipids were eluted with acetone/methanol, 9:1 (vol/vol). The neutral glycolipid fraction was then applied on a second Bio-Sil A column in chloroform/methanol, 98:2 (vol/vol). Glycolipids were then resolved with a linear solvent gradient comprising equal weights of chloroform/methanol, 15:1 (vol/vol), to chloroform/methanol, 4:1 (vol/vol). Digalactosyldiacylglycerol (DGDG) was purchased from Supelco (Ind), galactosylceramide (GC) was from Sigma (Ill), and phosphatidylethanolamine (PE) and phosphatidylserine (PS) were from Avanti. VT1 was purified as described (1). Rabbit anti-VT antibodies were kindly provided by S. Richardson (Department of Microbiology, Hospital for Sick Children). Monoclonal antibody against the B subunit of VT1 (13-C4) was a generous gift from A. O'Brien (Unifor...

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Section: Resultsmentioning

confidence: 99%

Induction of verotoxin sensitivity in receptor-deficient cell lines using the receptor glycolipid globotriosylceramide.

Waddell

Cohen

Lingwood

1990

Proc. Natl. Acad. Sci. U.S.A.

114

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“…Many testis-expressed genes also are found in brain (46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56). Similarly, there are many examples of differential mRNA processing in brain, the best known of which is the switch between calcitonin and calcitonin gene-related peptide (57,58).…”

Section: Discussionmentioning

confidence: 99%

Two distinct forms of the 64,000 M _r protein of the cleavage stimulation factor are expressed in mouse male germ cells

Wallace

Dass

Ravnik

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

107

158

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Polyadenylation in male germ cells differs from that in somatic cells. Many germ cell mRNAs do not contain the canonical AAUAAA in their 3 ends but are efficiently polyadenylated. To determine whether the 64,000 M r protein of the cleavage stimulation factor (CstF-64) is altered in male germ cells, we examined its expression in mouse testis. In addition to the 64,000 M r form, we found a related Ϸ70,000 M r protein that is abundant in testis, at low levels in brain, and undetectable in all other tissues examined. Expression of the Ϸ70,000 M r CstF-64 was limited to meiotic spermatocytes and postmeiotic spermatids in testis. In contrast, the 64,000 M r form was absent from spermatocytes, suggesting that the testis-specific CstF-64 might control expression of meiosis-specific genes. To determine why the 64,000 M r CstF-64 is not expressed in spermatocytes, we mapped its chromosomal location to the X chromosome in both mouse and human. CstF-64 may, therefore, be absent in spermatocytes because the X chromosome is inactivated during male meiosis. By extension, the testis-specific CstF-64 may be expressed from an autosomal homolog of the X chromosomal gene.Polyadenylation, the process of 3Ј end formation in eukaryotic mRNAs, is required for synthesis, transport, translation, and stability of most mRNAs (1-4). The sequence AAUAAA specifies accurate and efficient addition of poly(A) to the mRNA 3Ј end (5, 6). Substitutions at any position in this sequence diminish polyadenylation in vivo and in vitro (7-9), and 90-95% of sequenced mRNAs have AAUAAA in their 3Ј ends (1, 2). However, many mRNAs expressed in male germ cells do not have AAUAAA (refs. 10-13 and Table 1), but are nevertheless efficiently polyadenylated. Sequences such as UAUAAA, AUUAAA, UACAAA, and GAUAAA might substitute for the normal polyadenylation signal (10, 11), but no experimental evidence support these assertions.One hypothesis to account for the use of non-AAUAAA signals is that a protein involved in polyadenylation is altered in germ cells. A candidate is the 64,000 M r subunit of the cleavage stimulation factor (CstF-64) (14, 15), one of three polypeptides of CstF (16). CstF-64 has been shown to be essential for growth and viability of avian cells (17) and acts by binding to a U-or G͞U-rich region downstream of the cleavage site (18) whereas a 160,000 M r protein of the cleavage and polyadenylation specificity factor binds to the AAUAAA signal (19,20). CstF-64 governs polyadenylation site choice in adenovirus (21) and is involved in the immunoglobin switch from a membrane to secretory form during B-cell maturation (22)(23)(24). CstF also is involved in the cooperation of polyadenylation with splicing (25), and recent results show that it interacts with the C-terminal domain of RNA polymerase II and thus couples polyadenylation with transcription (26).Because of its essential role in somatic cell polyadenylation, we examined CstF-64 expression in male germ cells to test the hypothesis that it might contribute to polyadenylation of non-AA...

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“…Interestingly, it was reported that the SM4g also expressed on the cell surface of primary spermatocytes from the end of the leptoene stage or the zygotene stage and later [2,6,35]. Furthermore, a sulfolipid binding protein of 68 kDa, referred to as SLIP1, which was affinity purified from rat testis homogenates using a SM4g column [36], was believed to be homologues to HSP70-2 [29,37,38]. These reports could suggest that HSP70-2 might also contribute to the protection of CST activity of spermatocytes from heat stress.…”

Section: Discussionmentioning

confidence: 99%

Development and application of a system for seminolipid metabolism using mouse seminiferous tubules

et al. 2009

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A convenient tool for studying metabolism of seminolipid in testis was developed by using mouse isolated seminiferous tubules prepared by collagenase treatment. Because more than 99% of [(35)S]sulfate-incorporation was distributed in seminolipid, its metabolism in seminiferous tubules can be analyzed without disturbance of the other sulfolipids in this assay system. Furthermore, the contents of seminolipid and its precursor, galactosylalkylacylglycerol, which were determined by liquid chromatography-electrospray ionization mass spectrometry, did not change within a few hours, indicating that the incorporations of [(35)S]sulfate into seminolipid solely reflects the turnover rate of this sulfolipid. As an initial application of this system, we characterized heat-susceptibility of the seminolipid turnover rate in mouse seminiferous tubules. Severe heating (44 degrees C for 10 min) of the isolated seminiferous tubules suppressed the (35)S-incorporation into seminolipid to 47% of heating at scrotal temperature (32 degrees C for 70 min). In contrast, pretreatment of the testis in vivo under the same condition (44 degrees C for 10 min) did not decrease the seminolipid turnover rate in the isolated seminiferous tubules. In addition, the activity of galactocerebroside sulfotransferase decreased in the temperature-dependent manner in seminiferous tubules as well as crude tubular homogenates, where the activity is significantly more stable in the former than the latter. The newly developed system could provide useful basic data for further analyses of seminolipid metabolism in the testis.

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Sulfogalactolipid binding protein SLIP 1: A conserved function for a conserved protein

Cited by 36 publications

References 21 publications

Induction of verotoxin sensitivity in receptor-deficient cell lines using the receptor glycolipid globotriosylceramide.

Induction of verotoxin sensitivity in receptor-deficient cell lines using the receptor glycolipid globotriosylceramide.

Two distinct forms of the 64,000 M _r protein of the cleavage stimulation factor are expressed in mouse male germ cells

Development and application of a system for seminolipid metabolism using mouse seminiferous tubules

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Sulfogalactolipid binding protein SLIP 1: A conserved function for a conserved protein

Cited by 36 publications

References 21 publications

Induction of verotoxin sensitivity in receptor-deficient cell lines using the receptor glycolipid globotriosylceramide.

Induction of verotoxin sensitivity in receptor-deficient cell lines using the receptor glycolipid globotriosylceramide.

Two distinct forms of the 64,000 M r protein of the cleavage stimulation factor are expressed in mouse male germ cells

Development and application of a system for seminolipid metabolism using mouse seminiferous tubules

Contact Info

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Two distinct forms of the 64,000 M _r protein of the cleavage stimulation factor are expressed in mouse male germ cells