Molecular characterisation of ninein, a new coiled-coil protein of the centrosome

1996 ◽  
Vol 109 (1) ◽  
pp. 179-190 ◽  
Author(s):  
V. Bouckson-Castaing ◽  
M. Moudjou ◽  
D.J. Ferguson ◽  
S. Mucklow ◽  
Y. Belkaid ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Coiled Coil ◽  
Immunocytochemical Staining ◽  
Mouse Tissues ◽  
Coil Structure ◽  
Ef Hand ◽  
Alternatively Spliced ◽  
Polyclonal Antisera ◽  
And Function ◽  
Recombinant Fragments

We describe the cDNA cloning of ninein, a novel component of centrosomes. In the mouse, ninein is predicted to be an acidic protein (calculated pI of 4.8) with alternatively spliced forms of 245 kDa and 249 kDa that contain extensive regions of coiled-coil structure flanked by non-coiled ends. Other interesting features of this protein include an EF-hand-like domain, a potential GTP binding site and four leucine zipper domains. Specific polyclonal antisera were raised to two non-overlapping recombinant fragments of the protein and used to characterise the cellular distribution of ninein. Immunofluorescence and immunoelectron microscopy experiments with macrophage-like cells, Mm1, showed that ninein is localised specifically in the pericentriolar matrix of the centrosome. Studies with NIH3T3 fibroblasts demonstrated that ninein is associated with the centrosome throughout the cell cycle and can also be detected within nuclei at interphase. At mitosis ninein was also observed in association with the mitotic spindle. Immunocytochemical staining of mouse tissues showed that ninein was expressed in a heterogeneous fashion. Staining, if present, was always consistent with a centrosomal localisation and was never associated with nuclei. Ninein provides a new molecular tool for analysing the structure and function of the centrosome.

scholarly journals Kinetochore recruitment of CENP-F illustrates how paralog divergence shapes kinetochore composition and function

2018 ◽  
Author(s):  
Giuseppe Ciossani ◽  
Katharina Overlack ◽  
Arsen Petrovic ◽  
Pim Huis in ‘t Veld ◽  
Carolin Körner ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Kinase Domain ◽  
Mitotic Checkpoint ◽  
Checkpoint Control ◽  
Directed Motion ◽  
Coil Structure ◽  
Evolutionary Relatedness ◽  
Chromosome Alignment ◽  
And Function ◽  
Paralogous Proteins

The metazoan proteins CENP-E and CENP-F are components of a fibrous layer of mitotic kinetochores named the corona. Several features suggest that CENP-E and CENP-F are paralogs: they are very large (approximately 2700 and 3200 residues, respectively), rich in predicted coiled-coil structure, C-terminally prenylated, and endowed with microtubule-binding sites at their termini. In addition, CENP-E contains an ATP-hydrolyzing motor domain that promotes microtubule plus-end directed motion. Here, we show that CENP-E and CENP- F are recruited to mitotic kinetochores independently of the Rod-Zwilch-ZW10 (RZZ) complex, the main corona constituent. We identify selective interactions of CENP-E and CENP-F respectively with BubR1 and Bub1, paralogous proteins involved in mitotic checkpoint control and chromosome alignment. While BubR1 is dispensable for kinetochore localization of CENP-E, Bub1 is stringently required for CENP-F localization. Through biochemical reconstitution, we demonstrate that the CENP-E:BubR1 and CENP-F:Bub1 interactions are direct and require similar determinants, a dimeric coiled-coil in CENP-E or CENP-F and a kinase domain in BubR1 or Bub1. Our findings are consistent with the existence of ‘pseudo-symmetric’, paralogous Bub1:CENP-F and BubR1:CENP-E axes, supporting evolutionary relatedness of CENP-E and CENP-F.

scholarly journals Comparative analysis of the MyTH4-FERM myosins reveals insights into the determinants of actin track selection in polarized epithelia

2021 ◽  
pp. mbc.E20-07-0494
Author(s):  
Samaneh Matoo ◽  
Maura J. Graves ◽  
Prashun Acharya ◽  
Myoung Soo Choi ◽  
Zachary A. Storad ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Coiled Coil ◽  
Neck Region ◽  
Actin Networks ◽  
Cargo Proteins ◽  
Membrane Protrusions ◽  
Polarized Epithelia ◽  
And Function ◽  
Antiparallel Coiled Coil ◽  
Insight Into

MyTH4-FERM (MF) myosins evolved to play a role in the creation and function of a variety of actin-based membrane protrusions that extend from cells. Here, we performed an analysis of the MF myosins, Myo7A, Myo7B, and Myo10, to gain insight into how they select for their preferred actin networks. Using enterocytes that create spatially separated actin tracks in the form of apical microvilli and basal filopodia, we show that actin track selection is principally guided by the mode of oligomerization of the myosin along with the identity of the motor domain, with little influence from the specific composition of the lever arm. Chimeric variants of Myo7A and Myo7B fused to a leucine zipper parallel dimerization sequence in place of their native tails both selected apical microvilli as their tracks, while a truncated Myo10 used its native antiparallel coiled-coil to traffic to the tips of filopodia. Swapping lever arms between the Class 7 and 10 myosins did not change actin track preference. Surprisingly, fusing the motor-neck region of Myo10 to a leucine zipper or oligomerization sequences derived from the Myo7A and Myo7B cargo proteins USH1G and ANKS4B, respectively, re-encoded the actin track usage of Myo10 to apical microvilli with significant efficiency.

scholarly journals Occludin 1B, a Variant of the Tight Junction Protein Occludin

2000 ◽  
Vol 11 (2) ◽  
pp. 627-634 ◽  
Author(s):  
Zoia Muresan ◽  
David L. Paul ◽  
Daniel A. Goodenough
Keyword(s):  
Tight Junction ◽  
Base Pair ◽  
Mdck Cells ◽  
Human Colon ◽  
Reverse Transcription Pcr ◽  
Mouse Tissues ◽  
Junction Protein ◽  
Alternatively Spliced ◽  
Membrane Components ◽  
And Function

Occludin and claudin are the major integral membrane components of the mammalian tight junction. Although more than 11 distinct claudins have been identified, only 1 occludin transcript has been reported thus far. Therefore, we searched by reverse transcription–PCR for occludin-related sequences in Madin–Darby canine kidney (MDCK) mRNA and identified a transcript encoding an alternatively spliced form of occludin, designated occludin 1B. The occludin 1B transcript contained a 193-base pair insertion encoding a longer form of occludin with a unique N-terminal sequence of 56 amino acids. Analysis of the MDCK occludin gene revealed an exon containing the 193-base pair sequence between the exons encoding the original N terminus and the distal sequence, suggesting that occludin and occludin 1B arise from alternative splicing of one transcript. To assess the expression and distribution of occludin 1B, an antibody was raised against its unique N-terminal domain. Immunolabeling of occludin 1B in MDCK cells revealed a distribution indistinguishable from that of occludin. Furthermore, occludin 1B staining at cell-to-cell contacts was also found in cultured T84 human colon carcinoma cells and in frozen sections of mouse intestine. Immunoblots of various mouse tissues revealed broad coexpression of occludin 1B with occludin. The wide epithelial distribution and the conservation across species suggests a potentially important role for occludin 1B in the structure and function of the tight junction.

Leucine Is the Most Stabilizing Aliphatic Amino Acid in thedPosition of a Dimeric Leucine Zipper Coiled Coil

Biochemistry ◽  
1997 ◽  
Vol 36 (41) ◽  
pp. 12567-12573 ◽  
Author(s):  
Jaideep Moitra ◽  
Lászlo Szilák ◽  
Dmitry Krylov ◽  
Charles Vinson
Keyword(s):  
Amino Acid ◽  
Leucine Zipper ◽  
Coiled Coil ◽  
Aliphatic Amino Acid

scholarly journals Roles of the novel coiled-coil protein Rng10 in septum formation during fission yeast cytokinesis

2016 ◽  
Vol 27 (16) ◽  
pp. 2528-2541 ◽  
Author(s):  
Yajun Liu ◽  
I-Ju Lee ◽  
Mingzhai Sun ◽  
Casey A. Lower ◽  
Kurt W. Runge ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Rho Gtpases ◽  
Cellular Localization ◽  
Affinity Purification ◽  
Coiled Coil ◽  
The Novel ◽  
Septum Formation ◽  
Division Site ◽  
And Function

Rho GAPs are important regulators of Rho GTPases, which are involved in various steps of cytokinesis and other processes. However, regulation of Rho-GAP cellular localization and function is not fully understood. Here we report the characterization of a novel coiled-coil protein Rng10 and its relationship with the Rho-GAP Rga7 in fission yeast. Both rng10Δ and rga7Δ result in defective septum and cell lysis during cytokinesis. Rng10 and Rga7 colocalize on the plasma membrane at the cell tips during interphase and at the division site during cell division. Rng10 physically interacts with Rga7 in affinity purification and coimmunoprecipitation. Of interest, Rga7 localization is nearly abolished without Rng10. Moreover, Rng10 and Rga7 work together to regulate the accumulation and dynamics of glucan synthases for successful septum formation in cytokinesis. Our results show that cellular localization and function of the Rho-GAP Rga7 are regulated by a novel protein, Rng10, during cytokinesis in fission yeast.

scholarly journals Bioelectrocatalytic hydrogels from electron-conducting metallopolypeptides coassembled with bifunctional enzymatic building blocks

2008 ◽  
Vol 105 (40) ◽  
pp. 15275-15280 ◽  
Author(s):  
Ian R. Wheeldon ◽  
Joshua W. Gallaway ◽  
Scott Calabrese Barton ◽  
Scott Banta
Keyword(s):  
Polyphenol Oxidase ◽  
Building Block ◽  
Leucine Zipper ◽  
Electrical Contact ◽  
Building Blocks ◽  
Coiled Coils ◽  
Biofuel Cell ◽  
Random Coil ◽  
Catalytic Current ◽  
And Function

Here, we present two bifunctional protein building blocks that coassemble to form a bioelectrocatalytic hydrogel that catalyzes the reduction of dioxygen to water. One building block, a metallopolypeptide based on a previously designed triblock polypeptide, is electron-conducting. A second building block is a chimera of artificial α-helical leucine zipper and random coil domains fused to a polyphenol oxidase, small laccase (SLAC). The metallopolypeptide has a helix–random-helix secondary structure and forms a hydrogel via tetrameric coiled coils. The helical and random domains are identical to those fused to the polyphenol oxidase. Electron-conducting functionality is derived from the divalent attachment of an osmium bis-bipyrdine complex to histidine residues within the peptide. Attachment of the osmium moiety is demonstrated by mass spectroscopy (MS-MALDI-TOF) and cyclic voltammetry. The structure and function of the α-helical domains are confirmed by circular dichroism spectroscopy and by rheological measurements. The metallopolypeptide shows the ability to make electrical contact to a solid-state electrode and to the redox centers of modified SLAC. Neat samples of the modified SLAC form hydrogels, indicating that the fused α-helical domain functions as a physical cross-linker. The fusion does not disrupt dimer formation, a necessity for catalytic activity. Mixtures of the two building blocks coassemble to form a continuous supramolecular hydrogel that, when polarized, generates a catalytic current in the presence of oxygen. The specific application of the system is a biofuel cell cathode, but this protein-engineering approach to advanced functional hydrogel design is general and broadly applicable to biocatalytic, biosensing, and tissue-engineering applications.

Abstract 250: Haploinsufficiency of Muscle-Enriched A-Type Lamin Interacting Protein (MLIP) Manifests as Enlarged Dilated Hearts

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Patrick Burgon ◽  
Julia Lockwood ◽  
Glenn Wells ◽  
Alexandre Blais
Keyword(s):  
Heart Development ◽  
Left Ventricular ◽  
Lamin A ◽  
Interacting Protein ◽  
Cellular Hypertrophy ◽  
Cellular Source ◽  
Alternatively Spliced ◽  
Normal Body Weight ◽  
Heart Size ◽  
And Function

Approximately 116 unique mutations in the lamin A/C gene have been described to date that are associated with dilated cardiomyopathy. We recently reported the discovery of MLIP through its interaction with lamin A/C. MLIP is expressed ubiquitously and most abundantly in heart, skeletal and smooth muscle of amniotes (mammals, reptiles and birds) and has no paralogous homologue suggesting no functional redundancy. The MLIP gene encodes at least seven, alternatively spliced, LMNA-interacting factors that possess several structural motifs not found in any other protein. The MLIP isoforms pattern of expression differs between each of the tissues with heart being the most heterogeneous. Down-regulation of lamin A/C expression by shRNA results in the up-regulation and mis-localization of MLIP. In addition to interacting and co-localizing with lamin A/C we also demonstrated that MLIP localizes to micro-domains in the nucleus with promyelocytic leukemia protein (PML) in close proximity to chromatin. MLIP's biological function still remains elusive. Eight week old hemizygous MLIP null mice develop enlarged hearts with a significant increase in heart to body weights (MLIP+/+ 5.62mg/g vs MLIP+/- 10.73mg/g, p<0.0001 n=7) with an overall 30% increase in the anterior-posterior ventricle length of MLIP hearts while maintaining a normal body weight (Figure). Echocardiographic analysis of MLIP+/- mice revealed that their hearts as having a significant (p3.93mm with a significant (p=0.011, n=12) reduction of left ventricular fractional shorting (LVFS) 31% when compare to littermate controls. Histological analysis of the hearts showed no overt phenotype other than an overall increase in the size of the MLIP+/- hearts. The cellular source for the increase in heart size and mass remains to be determined if it is the product of an increase in the number of cardiomyocytes due to aberrant hyperplasia or an increase in cardiomyocyte size through cellular hypertrophy. In conclusion, MLIP is a newly discovered lamin interacting protein that may serve as a transcriptional regulator that impact genes involved in heart development, growth and function and provides a new signaling paradigm.

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