scholarly journals Membrane insertion function for SUN-KASH complex revealed by high resolution analysis of yeast centrosomes

2018 ◽  
Author(s):  
Jingjing Chen ◽  
Jennifer M. Gardner ◽  
Zulin Yu ◽  
Sarah E. Smith ◽  
Sean McKinney ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Spindle Pole ◽  
Bimolecular Fluorescence Complementation ◽  
Spin Component ◽  
Structured Illumination ◽  
Linc Complex ◽  
Protein Distribution ◽  
Protein Protein Interactions ◽  
Structured Illumination Microscopy ◽  
Complex Forms

AbstractBipolar spindle formation in yeast requires insertion of centrosomes (known as spindle pole bodies (SPBs)) into fenestrated regions of the nuclear envelope (NE). Using structured-illumination microscopy and bimolecular fluorescence complementation, we map protein distribution at SPB fenestra and interrogate protein-protein interactions with high spatial resolution. We find that the Sad1-UNC-84 (SUN) protein Mps3 forms a ring-like structure around the SPB, similar to toroids seen for components of the SPB insertion network (SPIN). Mps3 and the SPIN component Mps2 (a Klarsicht-ANC-1-Syne-1 domain (KASH)-like protein) form a novel non-canonical linker of nucleoskeleton and cytoskeleton (LINC) complex that is connected in both luminal and extraluminal domains. This hairpin-like LINC complex forms during SPB insertion, suggesting it functions in NE reorganization at the pore membrane. The LINC complex also controls the distribution of a soluble SPIN component Bbp1. Taken together our work shows that Mps3 is a fifth SPIN component and suggests both direct and indirect roles for the LINC complex in NE remodeling.

scholarly journals Yeast centrosome components form a noncanonical LINC complex at the nuclear envelope insertion site

2019 ◽  
Vol 218 (5) ◽  
pp. 1478-1490 ◽  
Author(s):  
Jingjing Chen ◽  
Jennifer M. Gardner ◽  
Zulin Yu ◽  
Sarah E. Smith ◽  
Sean McKinney ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Protein Interactions ◽  
Insertion Site ◽  
Spindle Pole ◽  
Bimolecular Fluorescence Complementation ◽  
Spin Component ◽  
Structured Illumination ◽  
Linc Complex ◽  
Protein Distribution ◽  
Structured Illumination Microscopy

Bipolar spindle formation in yeast requires insertion of centrosomes (known as spindle pole bodies [SPBs]) into fenestrated regions of the nuclear envelope (NE). Using structured illumination microscopy and bimolecular fluorescence complementation, we map protein distribution at SPB fenestrae and interrogate protein–protein interactions with high spatial resolution. We find that the Sad1-UNC-84 (SUN) protein Mps3 forms a ring-like structure around the SPB, similar to toroids seen for components of the SPB insertion network (SPIN). Mps3 and the SPIN component Mps2 (a Klarsicht-ANC-1-Syne-1 domain [KASH]–like protein) form a novel noncanonical linker of nucleoskeleton and cytoskeleton (LINC) complex that is connected in both luminal and extraluminal domains at the site of SPB insertion. The LINC complex also controls the distribution of a soluble SPIN component Bbp1. Taken together, our work shows that Mps3 is a fifth SPIN component and suggests both direct and indirect roles for the LINC complex in NE remodeling.

scholarly journals Roles of the 14-3-3 gene family in cotton flowering

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Na Sang ◽  
Hui Liu ◽  
Bin Ma ◽  
Xianzhong Huang ◽  
Lu Zhuo ◽  
...  
Keyword(s):  
Gene Family ◽  
Protein Interactions ◽  
Leucine Zipper ◽  
Expression Patterns ◽  
Bimolecular Fluorescence Complementation ◽  
Structural Motif ◽  
Virus Induced Gene Silencing ◽  
Protein Protein Interactions ◽  
Basic Leucine Zipper ◽  
Genome Wide

Abstract Background In plants, 14-3-3 proteins, also called GENERAL REGULATORY FACTORs (GRFs), encoded by a large multigene family, are involved in protein–protein interactions and play crucial roles in various physiological processes. No genome-wide analysis of the GRF gene family has been performed in cotton, and their functions in flowering are largely unknown. Results In this study, 17, 17, 31, and 17 GRF genes were identified in Gossypium herbaceum, G. arboreum, G. hirsutum, and G. raimondii, respectively, by genome-wide analyses and were designated as GheGRFs, GaGRFs, GhGRFs, and GrGRFs, respectively. A phylogenetic analysis revealed that these proteins were divided into ε and non-ε groups. Gene structural, motif composition, synteny, and duplicated gene analyses of the identified GRF genes provided insights into the evolution of this family in cotton. GhGRF genes exhibited diverse expression patterns in different tissues. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that the GhGRFs interacted with the cotton FLOWERING LOCUS T homologue GhFT in the cytoplasm and nucleus, while they interacted with the basic leucine zipper transcription factor GhFD only in the nucleus. Virus-induced gene silencing in G. hirsutum and transgenic studies in Arabidopsis demonstrated that GhGRF3/6/9/15 repressed flowering and that GhGRF14 promoted flowering. Conclusions Here, 82 GRF genes were identified in cotton, and their gene and protein features, classification, evolution, and expression patterns were comprehensively and systematically investigated. The GhGRF3/6/9/15 interacted with GhFT and GhFD to form florigen activation complexs that inhibited flowering. However, GhGRF14 interacted with GhFT and GhFD to form florigen activation complex that promoted flowering. The results provide a foundation for further studies on the regulatory mechanisms of flowering.

scholarly journals Redistribution of centrosomal proteins by centromeres and Polo kinase controls nuclear envelope breakdown

2020 ◽  
Author(s):  
Andrew J. Bestul ◽  
Zulin Yu ◽  
Jay R. Unruh ◽  
Sue L. Jaspersen
Keyword(s):  
Nuclear Envelope ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Ring Structure ◽  
Yeast Cells ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Spindle Formation ◽  
Nuclear Envelope Breakdown ◽  
Polo Kinase

AbstractProper mitotic progression in Schizosaccharomyces pombe requires partial nuclear envelope breakdown (NEBD) and insertion of the spindle pole body (SPB – yeast centrosome) to build the mitotic spindle. Linkage of the centromere to the SPB is vital to this process, but why that linkage is important is not well understood. Utilizing high-resolution structured illumination microscopy (SIM), we show that the conserved SUNprotein Sad1 and other SPB proteins redistribute during mitosis to form a ring complex around SPBs, which is a precursor for NEBD and spindle formation. Although the Polo kinase Plo1 is not necessary for Sad1 redistribution, it localizes to the SPB region connected to the centromere, and its activity is vital for SPB ring protein redistribution and for complete NEBD to allow for SPB insertion. Our results lead to a model in which centromere linkage to the SPB drives redistribution of Sad1 and Plo1 activation that in turn facilitate NEBD and spindle formation through building of an SPB ring structure.SummaryNuclear envelope breakdown is necessary for fission yeast cells to go through mitosis. Bestul et al. show that the SUN protein, Sad1, is vital in carrying out this breakdown and is regulated by the centromere and Polo kinase.

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