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Cheong HSJ, Nona M, Guerra SB, VanBerkum MF. The first quarter of the C-terminal domain of Abelson regulates the WAVE regulatory complex and Enabled in axon guidance. Neural Dev 2020; 15:7. [PMID: 32359359 PMCID: PMC7196227 DOI: 10.1186/s13064-020-00144-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/17/2020] [Indexed: 12/16/2022] Open
Abstract
Background Abelson tyrosine kinase (Abl) plays a key role in axon guidance in linking guidance receptors to actin dynamics. The long C-terminal domain (CTD) of Drosophila Abl is important for this role, and previous work identified the ‘first quarter’ (1Q) of the CTD as essential. Here, we link the physical interactions of 1Q binding partners to Abl’s function in axon guidance. Methods Protein binding partners of 1Q were identified by GST pulldown and mass spectrometry, and validated using axon guidance assays in the embryonic nerve cord and motoneurons. The role of 1Q was assessed genetically, utilizing a battery of Abl transgenes in combination with mutation or overexpression of the genes of pulled down proteins, and their partners in actin dynamics. The set of Abl transgenes had the following regions deleted: all of 1Q, each half of 1Q (‘eighths’, 1E and 2E) or a PxxP motif in 2E, which may bind SH3 domains. Results GST pulldown identified Hem and Sra-1 as binding partners of 1Q, and our genetic analyses show that both proteins function with Abl in axon guidance, with Sra-1 likely interacting with 1Q. As Hem and Sra-1 are part of the actin-polymerizing WAVE regulatory complex (WRC), we extended our analyses to Abi and Trio, which interact with Abl and WRC members. Overall, the 1Q region (and especially 2E and its PxxP motif) are important for Abl’s ability to work with WRC in axon guidance. These areas are also important for Abl’s ability to function with the actin regulator Enabled. In comparison, 1E contributes to Abl function with the WRC at the midline, but less so with Enabled. Conclusions The 1Q region, and especially the 2E region with its PxxP motif, links Abl with the WRC, its regulators Trio and Abi, and the actin regulator Ena. Removing 1E has specific effects suggesting it may help modulate Abl’s interaction with the WRC or Ena. Thus, the 1Q region of Abl plays a key role in regulating actin dynamics during axon guidance.
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Affiliation(s)
| | - Mark Nona
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA
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The histone chaperone NAP1L3 is required for haematopoietic stem cell maintenance and differentiation. Sci Rep 2018; 8:11202. [PMID: 30046127 PMCID: PMC6060140 DOI: 10.1038/s41598-018-29518-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 07/12/2018] [Indexed: 01/04/2023] Open
Abstract
Nucleosome assembly proteins (NAPs) are histone chaperones with an important role in chromatin structure and epigenetic regulation of gene expression. We find that high gene expression levels of mouse Nap1l3 are restricted to haematopoietic stem cells (HSCs) in mice. Importantly, with shRNA or CRISPR-Cas9 mediated loss of function of mouse Nap1l3 and with overexpression of the gene, the number of colony-forming cells and myeloid progenitor cells in vitro are reduced. This manifests as a striking decrease in the number of HSCs, which reduces their reconstituting activities in vivo. Downregulation of human NAP1L3 in umbilical cord blood (UCB) HSCs impairs the maintenance and proliferation of HSCs both in vitro and in vivo. NAP1L3 downregulation in UCB HSCs causes an arrest in the G0 phase of cell cycle progression and induces gene expression signatures that significantly correlate with downregulation of gene sets involved in cell cycle regulation, including E2F and MYC target genes. Moreover, we demonstrate that HOXA3 and HOXA5 genes are markedly upregulated when NAP1L3 is suppressed in UCB HSCs. Taken together, our findings establish an important role for NAP1L3 in HSC homeostasis and haematopoietic differentiation.
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Shao L, Chang J, Feng W, Wang X, Williamson EA, Li Y, Schajnovitz A, Scadden D, Mortensen LJ, Lin CP, Li L, Paulson A, Downing J, Zhou D, Hromas RA. The Wave2 scaffold Hem-1 is required for transition of fetal liver hematopoiesis to bone marrow. Nat Commun 2018; 9:2377. [PMID: 29915352 PMCID: PMC6006146 DOI: 10.1038/s41467-018-04716-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 05/16/2018] [Indexed: 01/08/2023] Open
Abstract
The transition of hematopoiesis from the fetal liver (FL) to the bone marrow (BM) is incompletely characterized. We demonstrate that the Wiskott–Aldrich syndrome verprolin-homologous protein (WAVE) complex 2 is required for this transition, as complex degradation via deletion of its scaffold Hem-1 causes the premature exhaustion of neonatal BM hematopoietic stem cells (HSCs). This exhaustion of BM HSC is due to the failure of BM engraftment of Hem-1−/− FL HSCs, causing early death. The Hem-1−/− FL HSC engraftment defect is not due to the lack of the canonical function of the WAVE2 complex, the regulation of actin polymerization, because FL HSCs from Hem-1−/− mice exhibit no defects in chemotaxis, BM homing, or adhesion. Rather, the failure of Hem-1−/− FL HSC engraftment in the marrow is due to the loss of c-Abl survival signaling from degradation of the WAVE2 complex. However, c-Abl activity is dispensable for the engraftment of adult BM HSCs into the BM. These findings reveal a novel function of the WAVE2 complex and define a mechanism for FL HSC fitness in the embryonic BM niche. Hematopoietic stem cells (HSCs) migrate from the fetal liver to the bone marrow (BM) during embryogenesis. Here the authors show that the WAVE2 complex scaffold Hem1 is required for engraftment of HSCs in BM, not through its canonical role regulating actin polymerization, but through c-Abl survival signaling.
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Affiliation(s)
- Lijian Shao
- Department of Pharmacology, University of Illinois Chicago, Chicago, IL, 60612, USA
| | - Jianhui Chang
- Department of Pharmaceutical Sciences and Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Wei Feng
- Department of Pharmaceutical Sciences and Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Xiaoyan Wang
- Department of Pharmaceutical Sciences and Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Elizabeth A Williamson
- Department of Medicine and Pathology, University of Florida, Gainesville, FL, 32610, USA
| | - Ying Li
- Department of Medicine and Pathology, University of Florida, Gainesville, FL, 32610, USA
| | - Amir Schajnovitz
- Stem Cell and Regenerative Biology Department, Harvard University, Cambridge, 02138, MA, USA.,Center for Regenerative Medicine, Massachusetts General Hospital, Boston, 02114, MA, USA.,Harvard Stem Cell Institute, Cambridge, MA, 02138, USA
| | - David Scadden
- Stem Cell and Regenerative Biology Department, Harvard University, Cambridge, 02138, MA, USA
| | - Luke J Mortensen
- Regenerative Medicine Center, University of Georgia, Athens, GA, 30602, USA
| | - Charles P Lin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Linheng Li
- Department of Pathology and Laboratory, Medicine University of Kansas, Kansas City, 66160, KA, USA
| | - Ariel Paulson
- Department of Pathology and Laboratory, Medicine University of Kansas, Kansas City, 66160, KA, USA.,Stowers Institute for Medical Research, Kansas City, MO, 66160, USA
| | - James Downing
- Department of Pathology and Laboratory Medicine, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Daohong Zhou
- Department of Pharmaceutical Sciences and Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA. .,Department of Pharmacodynamics, University of Florida, Gainesville, FL, 32610, USA.
| | - Robert A Hromas
- Office of the Dean and the Cancer Center, Long School of Medicine, University of Texas Health Science Center, San Antonio, TX, 78229, USA.
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Kelsom C, Lu W. Uncovering the link between malfunctions in Drosophila neuroblast asymmetric cell division and tumorigenesis. Cell Biosci 2012; 2:38. [PMID: 23151376 PMCID: PMC3524031 DOI: 10.1186/2045-3701-2-38] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 11/05/2012] [Indexed: 12/14/2022] Open
Abstract
Asymmetric cell division is a developmental process utilized by several organisms. On the most basic level, an asymmetric division produces two daughter cells, each possessing a different identity or fate. Drosophila melanogaster progenitor cells, referred to as neuroblasts, undergo asymmetric division to produce a daughter neuroblast and another cell known as a ganglion mother cell (GMC). There are several features of asymmetric division in Drosophila that make it a very complex process, and these aspects will be discussed at length. The cell fate determinants that play a role in specifying daughter cell fate, as well as the mechanisms behind setting up cortical polarity within neuroblasts, have proved to be essential to ensuring that neurogenesis occurs properly. The role that mitotic spindle orientation plays in coordinating asymmetric division, as well as how cell cycle regulators influence asymmetric division machinery, will also be addressed. Most significantly, malfunctions during asymmetric cell division have shown to be causally linked with neoplastic growth and tumor formation. Therefore, it is imperative that the developmental repercussions as a result of asymmetric cell division gone awry be understood.
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Affiliation(s)
- Corey Kelsom
- Department of Biochemistry and Molecular Biology, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, University of Southern California, 1425 San Pablo Street, Los Angeles, CA, 90033, USA.
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