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CD38/ADP-ribosyl cyclase: A new role in the regulation of osteoclastic bone resorption.

Sun L, Adebanjo OA, Moonga BS, Corisdeo S, Anandatheerthavarada HK, Biswas G, Arakawa T, Hakeda Y, Koval A, Sodam B, Bevis PJ, Moser AJ, Lai FA, Epstein S, Troen BR, Kumegawa M, Zaidi M - J. Cell Biol. (1999)

Bottom Line: We then examined the effects of CD38 on osteoclast function.IL-6, in turn, enhanced CD38 mRNA expression.Taken together, the results provide compelling evidence for a new role for CD38/ADP-ribosyl cyclase in the control of bone resorption, most likely exerted via cADPr.

View Article: PubMed Central - PubMed

Affiliation: Center for Osteoporosis and Skeletal Aging, Department of Medicine, Medical College of Pennsylvania and Veterans Affairs Medical Center, Philadelphia, Pennsylvania 19104, USA.

ABSTRACT
The multifunctional ADP-ribosyl cyclase, CD38, catalyzes the cyclization of NAD(+) to cyclic ADP-ribose (cADPr). The latter gates Ca(2+) release through microsomal membrane-resident ryanodine receptors (RyRs). We first cloned and sequenced full-length CD38 cDNA from a rabbit osteoclast cDNA library. The predicted amino acid sequence displayed 59, 59, and 50% similarity, respectively, to the mouse, rat, and human CD38. In situ RT-PCR revealed intense cytoplasmic staining of osteoclasts, confirming CD38 mRNA expression. Both confocal microscopy and Western blotting confirmed the plasma membrane localization of the CD38 protein. The ADP-ribosyl cyclase activity of osteoclastic CD38 was next demonstrated by its ability to cyclize the NAD(+) surrogate, NGD(+), to its fluorescent derivative cGDP-ribose. We then examined the effects of CD38 on osteoclast function. CD38 activation by an agonist antibody (A10) in the presence of substrate (NAD(+)) triggered a cytosolic Ca(2+) signal. Both ryanodine receptor modulators, ryanodine, and caffeine, markedly attenuated this cytosolic Ca(2+) change. Furthermore, the anti-CD38 agonist antibody expectedly inhibited bone resorption in the pit assay and elevated interleukin-6 (IL-6) secretion. IL-6, in turn, enhanced CD38 mRNA expression. Taken together, the results provide compelling evidence for a new role for CD38/ADP-ribosyl cyclase in the control of bone resorption, most likely exerted via cADPr.

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Predicted amino acid sequence of rabbit osteoclast CD38 compared with the known mouse, rat, and human sequences, as shown. The respective sequences were 69, 61, and 58% homologous with the rabbit CD38 sequence. Gaps are introduced to maximize homology. Asterisks indicate across-species identity of residues.
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Figure 2: Predicted amino acid sequence of rabbit osteoclast CD38 compared with the known mouse, rat, and human sequences, as shown. The respective sequences were 69, 61, and 58% homologous with the rabbit CD38 sequence. Gaps are introduced to maximize homology. Asterisks indicate across-species identity of residues.

Mentions: To obtain full-length CD38 cDNA clones, a rabbit osteoclast cDNA library was screened. A 293-bp CD38 cDNA coding region DNA fragment was initially cloned and used as probe. A single positive cDNA clone was identified after screening 1 × 107 independent phage recombinants; this contained a 2.8-kb EcoRI-XhoI insert in the plasmid pBluescript-SK (termed SL385). The sequence of the full-length SL385 CD38 insert was obtained. Sequence analysis confirmed the presence of the CD38 coding sequence and extended into 3′-untranslated region (Fig. 1). The osteoclast CD38 cDNA sequence was 71, 69, and 66% similar to corresponding full-length CD38 cDNA sequences of mouse, rat, and human CD38 (obtained from the GenBank database) (Fig. 1). No significant homology was found, however, between the sequence of the insert and any other sequence in the GenBank database. Fig. 2 shows the predicted amino acid sequence of the full-length rabbit osteoclastic CD38. There was a 59, 59, and 50% similarity between this sequence and that of mouse, rat, and human CD38 (GenBank), respectively. The relative sequence divergence suggests that the amplified DNA product codes for a yet uncharacterized member of the CD38 family of cyclases.


CD38/ADP-ribosyl cyclase: A new role in the regulation of osteoclastic bone resorption.

Sun L, Adebanjo OA, Moonga BS, Corisdeo S, Anandatheerthavarada HK, Biswas G, Arakawa T, Hakeda Y, Koval A, Sodam B, Bevis PJ, Moser AJ, Lai FA, Epstein S, Troen BR, Kumegawa M, Zaidi M - J. Cell Biol. (1999)

Predicted amino acid sequence of rabbit osteoclast CD38 compared with the known mouse, rat, and human sequences, as shown. The respective sequences were 69, 61, and 58% homologous with the rabbit CD38 sequence. Gaps are introduced to maximize homology. Asterisks indicate across-species identity of residues.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169484&req=5

Figure 2: Predicted amino acid sequence of rabbit osteoclast CD38 compared with the known mouse, rat, and human sequences, as shown. The respective sequences were 69, 61, and 58% homologous with the rabbit CD38 sequence. Gaps are introduced to maximize homology. Asterisks indicate across-species identity of residues.
Mentions: To obtain full-length CD38 cDNA clones, a rabbit osteoclast cDNA library was screened. A 293-bp CD38 cDNA coding region DNA fragment was initially cloned and used as probe. A single positive cDNA clone was identified after screening 1 × 107 independent phage recombinants; this contained a 2.8-kb EcoRI-XhoI insert in the plasmid pBluescript-SK (termed SL385). The sequence of the full-length SL385 CD38 insert was obtained. Sequence analysis confirmed the presence of the CD38 coding sequence and extended into 3′-untranslated region (Fig. 1). The osteoclast CD38 cDNA sequence was 71, 69, and 66% similar to corresponding full-length CD38 cDNA sequences of mouse, rat, and human CD38 (obtained from the GenBank database) (Fig. 1). No significant homology was found, however, between the sequence of the insert and any other sequence in the GenBank database. Fig. 2 shows the predicted amino acid sequence of the full-length rabbit osteoclastic CD38. There was a 59, 59, and 50% similarity between this sequence and that of mouse, rat, and human CD38 (GenBank), respectively. The relative sequence divergence suggests that the amplified DNA product codes for a yet uncharacterized member of the CD38 family of cyclases.

Bottom Line: We then examined the effects of CD38 on osteoclast function.IL-6, in turn, enhanced CD38 mRNA expression.Taken together, the results provide compelling evidence for a new role for CD38/ADP-ribosyl cyclase in the control of bone resorption, most likely exerted via cADPr.

View Article: PubMed Central - PubMed

Affiliation: Center for Osteoporosis and Skeletal Aging, Department of Medicine, Medical College of Pennsylvania and Veterans Affairs Medical Center, Philadelphia, Pennsylvania 19104, USA.

ABSTRACT
The multifunctional ADP-ribosyl cyclase, CD38, catalyzes the cyclization of NAD(+) to cyclic ADP-ribose (cADPr). The latter gates Ca(2+) release through microsomal membrane-resident ryanodine receptors (RyRs). We first cloned and sequenced full-length CD38 cDNA from a rabbit osteoclast cDNA library. The predicted amino acid sequence displayed 59, 59, and 50% similarity, respectively, to the mouse, rat, and human CD38. In situ RT-PCR revealed intense cytoplasmic staining of osteoclasts, confirming CD38 mRNA expression. Both confocal microscopy and Western blotting confirmed the plasma membrane localization of the CD38 protein. The ADP-ribosyl cyclase activity of osteoclastic CD38 was next demonstrated by its ability to cyclize the NAD(+) surrogate, NGD(+), to its fluorescent derivative cGDP-ribose. We then examined the effects of CD38 on osteoclast function. CD38 activation by an agonist antibody (A10) in the presence of substrate (NAD(+)) triggered a cytosolic Ca(2+) signal. Both ryanodine receptor modulators, ryanodine, and caffeine, markedly attenuated this cytosolic Ca(2+) change. Furthermore, the anti-CD38 agonist antibody expectedly inhibited bone resorption in the pit assay and elevated interleukin-6 (IL-6) secretion. IL-6, in turn, enhanced CD38 mRNA expression. Taken together, the results provide compelling evidence for a new role for CD38/ADP-ribosyl cyclase in the control of bone resorption, most likely exerted via cADPr.

Show MeSH