Dr. Qiwen Deng

All Publications

• The calcium signaling enzyme CD38 - a paradigm for membrane topology defining distinct protein functions. Cell calcium Lee, H. C., Deng, Q. W., Zhao, Y. J. 2022; 101: 102514

  Abstract

  CD38 is a single-pass transmembrane enzyme catalyzing the synthesis of two nucleotide second messengers, cyclic ADP-ribose (cADPR) from NAD and nicotinic acid adenine dinucleotide phosphate (NAADP) from NADP. The former mediates the mobilization of the endoplasmic Ca2+-stores in response to a wide range of stimuli, while NAADP targets the endo-lysosomal stores. CD38 not only possesses multiple enzymatic activities, it also exists in two opposite membrane orientations. Type III CD38 has the catalytic domain facing the cytosol and is responsible for producing cellular cADPR. The type II CD38 has an opposite orientation and is serving as a surface receptor mediating extracellular functions such as cell adhesion and lymphocyte activation. Its ecto-NADase activity also contributes to the recycling of external NAD released by apoptosis. Endocytosis can deliver surface type II CD38 to endo-lysosomes, which acidic environment favors the production of NAADP. This article reviews the rationale and evidence that have led to CD38 as a paradigm for membrane topology defining distinct functions of proteins. Also described is the recent discovery of a hitherto unknown cADPR-synthesizing enzyme, SARM1, ushering in a new frontier in cADPR-mediated Ca2+-signaling.

  View details for DOI 10.1016/j.ceca.2021.102514

  View details for PubMedID 34896700

• GALA peptide improves the potency of nanobody-drug conjugates by lipid-induced helix formation. Chemical communications (Cambridge, England) Chen, Y. J., Deng, Q. W., Wang, L., Guo, X. C., Yang, J. Y., Li, T., Xu, Z., Lee, H. C., Zhao, Y. J. 2021; 57 (12): 1434-1437

  Abstract

  A novel nanobody-drug conjugate (NDC) was constructed by incorporating an amphipathic peptide, GALA, which improved the cytotoxicity by one to two orders of magnitude. Mechanistic studies demonstrate that tethering to lipids induces GALA to form a helix, which dramatically enhances endocytosis. Our work provides a general strategy not only for improving the anti-cancer efficacy of protein-drug conjugates but also for increasing the efficiency of other types of endocytosis-dependent cell delivery.

  View details for DOI 10.1039/d0cc07706b

  View details for PubMedID 33514953

• The transferrin receptor CD71 regulates type II CD38, revealing tight topological compartmentalization of intracellular cyclic ADP-ribose production JOURNAL OF BIOLOGICAL CHEMISTRY Deng, Q., Zhang, J., Li, T., He, W., Fang, L., Lee, H., Zhao, Y. 2019; 294 (42): 15293–303

  Abstract

  The CD38 molecule (CD38) catalyzes biogenesis of the calcium-mobilizing messenger cyclic ADP-ribose (cADPR). CD38 has dual membrane orientations, and type III CD38, with its catalytic domain facing the cytosol, has low abundance but is efficient in cyclizing cytosolic NAD to produce cADPR. The role of cell surface type II CD38 in cellular cADPR production is unknown. Here we modulated type II CD38 expression and assessed the effects of this modulation on cADPR levels. We developed a photoactivatable cross-linking probe based on a CD38 nanobody, and, combining it with MS analysis, we discovered that cell surface CD38 interacts with CD71. CD71 knockdown increased CD38 levels, and CD38 knockout reciprocally increased CD71, and both could be cocapped and coimmunoprecipitated. We constructed a chimera comprising the N-terminal segment of CD71 and a CD38 nanobody to mimic CD71's ligand property. Overexpression of this chimera induced a dramatically large decrease in CD38 via lysosomes. Remarkably, cellular cADPR levels did not decrease correspondingly. Bafilomycin-mediated blockade of lysosomal degradation greatly elevated active type II CD38 by trapping it in the lysosomes but also did not increase cADPR levels. Retention of type II CD38 in the endoplasmic reticulum (ER) by expressing an ER construct that prevented its transport to the cell surface likewise did not change cADPR levels. These results provide first and direct evidence that cADPR biogenesis occurs in the cytosol and is catalyzed mainly by type III CD38 and that type II CD38, compartmentalized in the ER or lysosomes or on the cell surface, contributes only minimally to cADPR biogenesis.

  View details for DOI 10.1074/jbc.RA119.010010

  View details for Web of Science ID 000499248700009

  View details for PubMedID 31434741

  View details for PubMedCentralID PMC6802523

• CD38 produces nicotinic acid adenosine dinucleotide phosphate in the lysosome JOURNAL OF BIOLOGICAL CHEMISTRY Fang, C., Li, T., Li, Y., Xu, G., Deng, Q., Chen, Y., Hou, Y., Lee, H., Zhao, Y. 2018; 293 (21): 8151-8160

  Abstract

  Nicotinic acid adenosine dinucleotide phosphate (NAADP) is a Ca2+-mobilizing second messenger that regulates a wide range of biological activities. However, the mechanism of its biogenesis remains controversial. CD38 is the only enzyme known to catalyze NAADP synthesis from NADP and nicotinic acid. CD38-mediated catalysis requires an acidic pH, suggesting that NAADP may be produced in acidic endolysosomes, but this hypothesis is untested. In this study, using human cell lines, we specifically directed CD38 to the endolysosomal system and assessed cellular NAADP production. First, we found that nanobodies targeting various epitopes on the C-terminal domain of CD38 could bind to cell surface-localized CD38 and induce its endocytosis. We also found that CD38 internalization occurred via a clathrin-dependent pathway, delivered CD38 to the endolysosome, and elevated intracellular NAADP levels. We also created a CD38 variant for lysosome-specific expression, which not only withstood the degradative environment in the lysosome, but was also much more active than WT CD38 in elevating cellular NAADP levels. Supplementing CD38-expressing cells with nicotinic acid substantially increased cellular NAADP levels. These results demonstrate that endolysosomal CD38 can produce NAADP in human cells. They further suggest that CD38's compartmentalization to the lysosome may allow for its regulation via substrate access, rather than enzyme activation, thereby providing a reliable mechanism for regulating cellular NAADP production.

  View details for DOI 10.1074/jbc.RA118.002113

  View details for Web of Science ID 000433224600020

  View details for PubMedID 29632067

  View details for PubMedCentralID PMC5971459

• Development of Stabilized Peptide-Based PROTACs against Estrogen Receptor α. ACS chemical biology Jiang, Y., Deng, Q., Zhao, H., Xie, M., Chen, L., Yin, F., Qin, X., Zheng, W., Zhao, Y., Li, Z. 2018; 13 (3): 628-635

  Abstract

  Peptide modulators targeting protein-protein interactions (PPIs) exhibit greater potential than small-molecule drugs in several important aspects including facile modification and relative large contact surface area. Stabilized peptides constructed by variable chemistry methods exhibit improved peptide stability and cell permeability compared to that of the linears. Herein, we designed a stabilized peptide-based proteolysis-targeting chimera (PROTAC) targeting estrogen receptor α (ERα) by tethering an N-terminal aspartic acid cross-linked stabilized peptide ERα modulator (TD-PERM) with a pentapeptide that binds the Von Hippel-Lindau (VHL) E3 ubiquitin ligase complex. The resulting heterobifunctional peptide (TD-PROTAC) selectively recruits ERα to the VHL E3 ligase complex, leading to the degradation of ERα in a proteasome-dependent manner. Compared with the control peptides, TD-PROTAC shows significantly enhanced activities in reducing the transcription of the ERα-downstream genes and inhibiting the proliferation of ERα-positive breast cancer cells. In addition, in vivo experiments indicate that TD-PROTAC leads to tumor regression in the MCF-7 mouse xenograft model. This work is a successful attempt to construct PROTACs based on cell-permeable stabilized peptides, which significantly broadens the chemical space of PROTACs and stabilized peptides.

  View details for DOI 10.1021/acschembio.7b00985

  View details for PubMedID 29271628

• Immuno-targeting the multifunctional CD38 using nanobody SCIENTIFIC REPORTS Li, T., Qi, S., Unger, M., Hou, Y., Deng, Q., Liu, J., Lam, C. C., Wang, X., Xin, D., Zhang, P., Koch-Nolte, F., Hao, Q., Zhang, H., Lee, H., Zhao, Y. 2016; 6: 27055

  Abstract

  CD38, as a cell surface antigen is highly expressed in several hematologic malignancies including multiple myeloma (MM) and has been proven to be a good target for immunotherapy of the disease. CD38 is also a signaling enzyme responsible for the metabolism of two novel calcium messenger molecules. To be able to target this multifunctional protein, we generated a series of nanobodies against CD38 with high affinities. Crystal structures of the complexes of CD38 with the nanobodies were solved, identifying three separate epitopes on the carboxyl domain. Chromobodies, engineered by tagging the nanobody with fluorescence proteins, provide fast, simple and versatile tools for quantifying CD38 expression. Results confirmed that CD38 was highly expressed in malignant MM cells compared with normal white blood cells. The immunotoxin constructed by splicing the nanobody with a bacterial toxin, PE38 shows highly selective cytotoxicity against patient-derived MM cells as well as the cell lines, with half maximal effective concentration reaching as low as 10(-11) molar. The effectiveness of the immunotoxin can be further increased by stimulating CD38 expression using retinoid acid. These results set the stage for the development of clinical therapeutics as well as diagnostic screening for myeloma.

  View details for DOI 10.1038/srep27055

  View details for Web of Science ID 000376850300001

  View details for PubMedID 27251573

  View details for PubMedCentralID PMC4890012