scholarly journals LDB1 Enforces Stability on Direct and Indirect Oncoprotein Partners in Leukemia

2020 ◽  
Vol 40 (12) ◽  
Author(s):  
Justin H. Layer ◽  
Michael Christy ◽  
Lindsey Placek ◽  
Derya Unutmaz ◽  
Yan Guo ◽  
...  
Keyword(s):  
Protein Complex ◽  
Cell Formation ◽  
Macromolecular Complex ◽  
Cell Specification ◽  
Hematopoietic Stem ◽  
Protein Partners ◽  
Gata Transcription Factors ◽  
Macromolecular Protein ◽  
Protein Tagging ◽  
Protein Complex Assembly

ABSTRACT The LMO2/LDB1 macromolecular complex is critical in hematopoietic stem and progenitor cell specification and in the development of acute leukemia. This complex is comprised of core subunits of LMO2 and LDB1 as well as single-stranded DNA-binding protein (SSBP) cofactors and DNA-binding basic helix-loop-helix (bHLH) and GATA transcription factors. We analyzed the steady-state abundance and kinetic stability of LMO2 and its partners via Halo protein tagging in conjunction with variant proteins deficient in binding their respective direct protein partners. We discovered a hierarchy of protein stabilities (with half-lives in descending order) as follows: LDB1 > SSBP > LMO2 > TAL1. Importantly, LDB1 is a remarkably stable protein that confers enhanced stability upon direct and indirect partners, thereby nucleating the formation of the multisubunit protein complex. The data imply that free subunits are more rapidly degraded than those incorporated within the LMO2/LDB1 complex. Our studies provided significant insights into LMO2/LDB1 macromolecular protein complex assembly and stability, which has implications for understanding its role in blood cell formation and for therapeutically targeting this complex in human leukemias.

scholarly journals Live cell kinetic analysis of the LMO2/LDB1 leukemogenic protein complex reveals a hierarchy of turnover with implications for complex assembly

2019 ◽  
Author(s):  
Justin H. Layer ◽  
Michael Christy ◽  
Lindsay Placek ◽  
Derya Unutmaz ◽  
Yan Guo ◽  
...  
Keyword(s):  
Protein Complex ◽  
Protein Complexes ◽  
Cell Formation ◽  
Macromolecular Complex ◽  
Cellular Functions ◽  
Cell Specification ◽  
Complex Assembly ◽  
Hematopoietic Stem ◽  
Protein Partners ◽  
Macromolecular Protein

SummaryMultisubunit protein complexes operate in many cellular functions. The LDB1/LMO2 macromolecular complex has been posited to be critical in hematopoietic stem and progenitor cell specification and in the development of acute leukemia. This complex is comprised of core subunits of LMO2 and LDB1 as well as bHLH and GATA transcription factors. We analyzed the steady state abundance and kinetic stability of LMO2 and its partners via HALO protein tagging in conjunction with variant proteins deficient in binding their respective direct protein partners. We discovered a hierarchy of protein stability, with half lives in descending order: LDB1>SSBP>LMO2>TAL1. Importantly, LDB1 conferred enhanced stability upon each and every subunit component and nucleated the formation of the multisubunit protein complex. Our studies provide significant insights into LDB1/LMO2 macromolecular protein complex assembly and stability, which has implications for understanding its role in blood cell formation and for therapeutically targeting this complex in human leukemias.

scholarly journals Visualizing the Dynamics of Dystrophin Protein Complex Assembly in Living Cells

2005 ◽  
Vol 11 (S02) ◽  
Author(s):  
R A Draviam ◽  
B Wang ◽  
S Shand ◽  
X Xiao ◽  
S C Watkins
Keyword(s):  
Protein Complex ◽  
Living Cells ◽  
Complex Assembly ◽  
Dystrophin Protein ◽  
Protein Complex Assembly

scholarly journals Sequential regulation of hemogenic fate and hematopoietic stem and progenitor cell formation from arterial endothelium by Ezh1/2

2021 ◽  
Author(s):  
Rebecca A. Soto ◽  
Mohamad Ali T. Najia ◽  
Mariam Hachimi ◽  
Jenna M. Frame ◽  
Gabriel A. Yette ◽  
...  
Keyword(s):  
Progenitor Cell ◽  
Cell Formation ◽  
Hematopoietic Stem ◽  
Arterial Endothelium

scholarly journals Tyrosyl-tRNA synthetase stimulates thrombopoietin-independent hematopoiesis accelerating recovery from thrombocytopenia

2018 ◽  
Vol 115 (35) ◽  
pp. E8228-E8235 ◽  
Author(s):  
Taisuke Kanaji ◽  
My-Nuong Vo ◽  
Sachiko Kanaji ◽  
Alessandro Zarpellon ◽  
Ryan Shapiro ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Formation ◽  
Induced Pluripotent Stem Cell ◽  
Trna Synthetase ◽  
Monocytic Cells ◽  
Formation Continue ◽  
Hematopoietic Stem ◽  
Culture Production ◽  
High Ploidy ◽  
Induced Pluripotent

New mechanisms behind blood cell formation continue to be uncovered, with therapeutic approaches for hematological diseases being of great interest. Here we report an enzyme in protein synthesis, known for cell-based activities beyond translation, is a factor inducing megakaryocyte-biased hematopoiesis, most likely under stress conditions. We show an activated form of tyrosyl-tRNA synthetase (YRSACT), prepared either by rationally designed mutagenesis or alternative splicing, induces expansion of a previously unrecognized high-ploidy Sca-1+ megakaryocyte population capable of accelerating platelet replenishment after depletion. Moreover, YRSACT targets monocytic cells to induce secretion of transacting cytokines that enhance megakaryocyte expansion stimulating the Toll-like receptor/MyD88 pathway. Platelet replenishment by YRSACT is independent of thrombopoietin (TPO), as evidenced by expansion of the megakaryocytes from induced pluripotent stem cell-derived hematopoietic stem cells from a patient deficient in TPO signaling. We suggest megakaryocyte-biased hematopoiesis induced by YRSACT offers new approaches for treating thrombocytopenia, boosting yields from cell-culture production of platelet concentrates for transfusion, and bridging therapy for hematopoietic stem cell transplantation.

scholarly journals Retinal Cone Photoreceptors Require Phosducin-Like Protein 1 for G Protein Complex Assembly and Signaling

PLoS ONE ◽  
2015 ◽  
Vol 10 (2) ◽  
pp. e0117129 ◽  
Author(s):  
Christopher M. Tracy ◽  
Alexander V. Kolesnikov ◽  
Devon R. Blake ◽  
Ching-Kang Chen ◽  
Wolfgang Baehr ◽  
...  
Keyword(s):  
G Protein ◽  
Protein Complex ◽  
Cone Photoreceptors ◽  
Complex Assembly ◽  
Retinal Cone ◽  
Protein Complex Assembly

scholarly journals Developmental trajectory of prehematopoietic stem cell formation from endothelium

Blood ◽  
2020 ◽  
Vol 136 (7) ◽  
pp. 845-856 ◽  
Author(s):  
Qin Zhu ◽  
Peng Gao ◽  
Joanna Tober ◽  
Laura Bennett ◽  
Changya Chen ◽  
...  
Keyword(s):  
Single Cell ◽  
Fetal Liver ◽  
Developmental Trajectories ◽  
Cell Formation ◽  
Intermediate Stage ◽  
Chromatin Accessibility ◽  
Small Population ◽  
Developmental Trajectory ◽  
Mammalian Embryo ◽  
Hematopoietic Stem

Abstract Hematopoietic stem and progenitor cells (HSPCs) in the bone marrow are derived from a small population of hemogenic endothelial (HE) cells located in the major arteries of the mammalian embryo. HE cells undergo an endothelial to hematopoietic cell transition, giving rise to HSPCs that accumulate in intra-arterial clusters (IAC) before colonizing the fetal liver. To examine the cell and molecular transitions between endothelial (E), HE, and IAC cells, and the heterogeneity of HSPCs within IACs, we profiled ∼40 000 cells from the caudal arteries (dorsal aorta, umbilical, vitelline) of 9.5 days post coitus (dpc) to 11.5 dpc mouse embryos by single-cell RNA sequencing and single-cell assay for transposase-accessible chromatin sequencing. We identified a continuous developmental trajectory from E to HE to IAC cells, with identifiable intermediate stages. The intermediate stage most proximal to HE, which we term pre-HE, is characterized by increased accessibility of chromatin enriched for SOX, FOX, GATA, and SMAD motifs. A developmental bottleneck separates pre-HE from HE, with RUNX1 dosage regulating the efficiency of the pre-HE to HE transition. A distal candidate Runx1 enhancer exhibits high chromatin accessibility specifically in pre-HE cells at the bottleneck, but loses accessibility thereafter. Distinct developmental trajectories within IAC cells result in 2 populations of CD45+ HSPCs; an initial wave of lymphomyeloid-biased progenitors, followed by precursors of hematopoietic stem cells (pre-HSCs). This multiomics single-cell atlas significantly expands our understanding of pre-HSC ontogeny.

scholarly journals Transcriptome Dynamics of Hematopoietic Stem Cell Formation Revealed Using a Combinatorial Runx1 and Ly6a Reporter System

2020 ◽  
Vol 14 (5) ◽  
pp. 956-971 ◽  
Author(s):  
Michael J. Chen ◽  
Edroaldo Lummertz da Rocha ◽  
Patrick Cahan ◽  
Caroline Kubaczka ◽  
Phoebe Hunter ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Cell Formation ◽  
Reporter System ◽  
Hematopoietic Stem

scholarly journals Protein partners of deubiquitinating enzymes

2008 ◽  
Vol 414 (2) ◽  
pp. 161-175 ◽  
Author(s):  
Karen H. Ventii ◽  
Keith D. Wilkinson
Keyword(s):  
Protein Modification ◽  
Ubiquitin Ligases ◽  
Gene Families ◽  
Macromolecular Complex ◽  
Deubiquitinating Enzymes ◽  
Macromolecular Complexes ◽  
Protein Partners ◽  
Regulatory Strategy ◽  
Catalytically Active ◽  
Ubiquitin Receptors

Protein modification by ubiquitin and ubiquitin-like molecules is a critical regulatory process. Like most regulated protein modifications, ubiquitination is reversible. Deubiquitination, the reversal of ubiquitination, is quickly being recognized as an important regulatory strategy. Nearly one hundred human DUBs (deubiquitinating enzymes) in five different gene families oppose the action of several hundred ubiquitin ligases, suggesting that both ubiquitination and its reversal are highly regulated and specific processes. It has long been recognized that ubiquitin ligases are modular enzyme systems that often depend on scaffolds and adaptors to deliver substrates to the catalytically active macromolecular complex. Although many DUBs bind ubiquitin with reasonable affinities (in the nM to μM range), a larger number have little affinity but exhibit robust catalytic capability. Thus it is apparent that these DUBs must acquire their substrates by binding the target protein in a conjugate or by associating with other macromolecular complexes. We would then expect that a study of protein partners of DUBs would reveal a variety of substrates, scaffolds, adaptors and ubiquitin receptors. In the present review we suggest that, like ligases, much of the regulation and specificity of deubiquitination arises from the association of DUBs with these protein partners.

GATA transcription factors and fat cell formation

2003 ◽  
Vol 16 (9) ◽  
pp. 585 ◽  
Author(s):  
Q. Tong ◽  
J. Tsai ◽  
G.S. Hotamisligil
Keyword(s):  
Transcription Factors ◽  
Cell Formation ◽  
Fat Cell ◽  
Gata Transcription Factors
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