scholarly journals Subcellular localization of full-length human myeloid leukemia factor 1 (MLF1) is independent of 14-3-3 proteins

2013 ◽  
Vol 18 (1) ◽  
Author(s):  
Manuela Molzan ◽  
Christian Ottmann
Keyword(s):  
Subcellular Localization ◽  
Nuclear Export ◽  
Myeloid Leukemia ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Physiological Function ◽  
Full Length ◽  
Interaction Partners ◽  
Functional Features ◽  
Nuclear Localization Sequences

AbstractMyeloid leukemia factor 1 (MLF1) is associated with the development of leukemic diseases such as acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). However, information on the physiological function of MLF1 is limited and mostly derived from studies identifying MLF1 interaction partners like CSN3, MLF1IP, MADM, Manp and the 14-3-3 proteins. The 14-3-3-binding site surrounding S34 is one of the only known functional features of the MLF1 sequence, along with one nuclear export sequence (NES) and two nuclear localization sequences (NLS). It was recently shown that the subcellular localization of mouse MLF1 is dependent on 14-3-3 proteins. Based on these findings, we investigated whether the subcellular localization of human MLF1 was also directly 14-3-3-dependent. Live cell imaging with GFP-fused human MLF1 was used to study the effects of mutations and deletions on its subcellular localization. Surprisingly, we found that the subcellular localization of full-length human MLF1 is 14-3-3-independent, and is probably regulated by other as-yet-unknown proteins.

scholarly journals MyTH4-FERM myosins have an ancient and conserved role in filopod formation

2016 ◽  
Vol 113 (50) ◽  
pp. E8059-E8068 ◽  
Author(s):  
Karl J. Petersen ◽  
Holly V. Goodson ◽  
Ashley L. Arthur ◽  
G. W. Gant Luxton ◽  
Anne Houdusse ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Null Mutant ◽  
Minimal Elements ◽  
Social Amoeba ◽  
Functional Conservation ◽  
Functional Homolog ◽  
The Social ◽  
Functional Features

The formation of filopodia in Metazoa and Amoebozoa requires the activity of myosin 10 (Myo10) in mammalian cells and of Dictyostelium unconventional myosin 7 (DdMyo7) in the social amoeba Dictyostelium. However, the exact roles of these MyTH4-FERM myosins (myosin tail homology 4-band 4.1, ezrin, radixin, moesin; MF) in the initiation and elongation of filopodia are not well defined and may reflect conserved functions among phylogenetically diverse MF myosins. Phylogenetic analysis of MF myosin domains suggests that a single ancestral MF myosin existed with a structure similar to DdMyo7, which has two MF domains, and that subsequent duplications in the metazoan lineage produced its functional homolog Myo10. The essential functional features of the DdMyo7 myosin were identified using quantitative live-cell imaging to characterize the ability of various mutants to rescue filopod formation in myo7-null cells. The two MF domains were found to function redundantly in filopod formation with the C-terminal FERM domain regulating both the number of filopodia and their elongation velocity. DdMyo7 mutants consisting solely of the motor plus a single MyTH4 domain were found to be capable of rescuing the formation of filopodia, establishing the minimal elements necessary for the function of this myosin. Interestingly, a chimeric myosin with the Myo10 MF domain fused to the DdMyo7 motor also was capable of rescuing filopod formation in the myo7-null mutant, supporting fundamental functional conservation between these two distant myosins. Together, these findings reveal that MF myosins have an ancient and conserved role in filopod formation.

scholarly journals Quantitative live-cell imaging and 3D modeling reveal critical functional features in the cytosolic complex of phagocyte NADPH oxidase

2019 ◽  
Vol 294 (11) ◽  
pp. 3824-3836 ◽  
Author(s):  
Cornelia S. Ziegler ◽  
Leïla Bouchab ◽  
Marc Tramier ◽  
Dominique Durand ◽  
Franck Fieschi ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
3D Modeling ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Phagocyte Nadph Oxidase ◽  
Functional Features

Analysis of the influence of subcellular localization of the HIV Rev protein on Rev-dependent gene expression by multi-fluorescence live-cell imaging

2006 ◽  
Vol 312 (4) ◽  
pp. 443-456 ◽  
Author(s):  
Horst Wolff ◽  
Kamyar Hadian ◽  
Manja Ziegler ◽  
Claudia Weierich ◽  
Susanne Kramer-Hammerle ◽  
...  
Keyword(s):  
Gene Expression ◽  
Subcellular Localization ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Rev Protein ◽  
Fluorescence Live Cell Imaging

scholarly journals Torsin ATPase deficiency leads to defects in nuclear pore biogenesis and sequestration of MLF2

2020 ◽  
Vol 219 (6) ◽  
Author(s):  
Anthony J. Rampello ◽  
Ethan Laudermilch ◽  
Nidhi Vishnoi ◽  
Sarah M. Prophet ◽  
Lin Shao ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Myeloid Leukemia ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Nuclear Pore ◽  
Ubiquitin Conjugation ◽  
Bleb Formation ◽  
Kinetics Of

Nuclear envelope herniations (blebs) containing FG-nucleoporins and ubiquitin are the phenotypic hallmark of Torsin ATPase manipulation. Both the dynamics of blebbing and the connection to nuclear pore biogenesis remain poorly understood. We employ a proteomics-based approach to identify myeloid leukemia factor 2 (MLF2) as a luminal component of the bleb. Using an MLF2-based live-cell imaging platform, we demonstrate that nuclear envelope blebbing occurs rapidly and synchronously immediately after nuclear envelope reformation during mitosis. Bleb formation is independent of ubiquitin conjugation within the bleb, but strictly dependent on POM121, a transmembrane nucleoporin essential for interphase nuclear pore biogenesis. Nup358, a late marker for interphase nuclear pore complex (NPC) biogenesis, is underrepresented relative to FG-nucleoporins in nuclear envelopes of Torsin-deficient cells. The kinetics of bleb formation, its dependence on POM121, and a reduction of mature NPCs in Torsin-deficient cells lead us to conclude that the hallmark phenotype of Torsin manipulation represents aberrant NPC intermediates.

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