The evolution, complex structures and function of septin proteins

Cao, Lanqing; Yu, Wenbo; Wu, Yanhua; Liu, Yu

doi:10.1007/s00018-009-0087-2

Cited by 64 publications

(64 citation statements)

References 137 publications

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“…Although there is still some controversy about exactly how the core septins are arranged at the motherdaughter neck, their ability to form continuous filaments appears to be essential for localization to the membrane as visible rings and for their function as diffusion barriers (43). Recently, septins have been characterized in several filamentous fungi where they play a variety of roles and take on a range of morphologies and localizations (11,24,49). The filamentous fungus A. nidulans has five septins (AspA to AspE), one representative of each of the S. cerevisiae core septins and a single septin found only in filamentous fungi (AspA is orthologous to Cdc11, AspB is orthologous to Cdc3, AspC is orthologous to Cdc12, and AspD is orthologous to Cdc10; AspE is found only in filamentous fungi.)…”

Section: Discussionmentioning

confidence: 99%

The Septin AspB in Aspergillus nidulans Forms Bars and Filaments and Plays Roles in Growth Emergence and Conidiation

2012

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In yeast, septins form rings at the mother-bud neck and function as diffusion barriers. In animals, septins form filaments that can colocalize with other cytoskeletal elements. In the filamentous fungus Aspergillus nidulans there are five septin genes, aspA (an ortholog of Saccharomyces cerevisiae CDC11), aspB (an ortholog of S. cerevisiae CDC3), aspC (an ortholog of S. cerevisiae CDC12), aspD (an ortholog of S. cerevisiae CDC10), and aspE (found only in filamentous fungi). The aspB gene was previously reported to be the most highly expressed Aspergillus nidulans septin and to be essential. Using improved gene targeting techniques, we found that deletion of aspB is not lethal but results in delayed septation, increased emergence of germ tubes and branches, and greatly reduced conidiation. We also found that AspB-green fluorescent protein (GFP) localizes as rings and collars at septa, branches, and emerging layers of the conidiophore and as bars and filaments in conidia and hyphae. Bars are found in dormant and isotropically expanding conidia and in subapical nongrowing regions of hyphae and display fast movements. Filaments form as the germ tube emerges, localize to hyphal and branch tips, and display slower movements. All visible AspB-GFP structures are retained in ⌬aspD and lost in ⌬aspA and ⌬aspC strains. Interestingly, in the ⌬aspE mutant, AspB-GFP rings, bars, and filaments are visible in early growth, but AspB-GFP rods and filaments disappear after septum formation. AspE orthologs are only found in filamentous fungi, suggesting that this class of septins might be required for stability of septin bars and filaments in highly polar cells. Septins are evolutionarily conserved GTP binding proteins that form complexes and are increasingly viewed as cytoskeletal elements (62). Septins are found in all eukaryotes except higher plants (20,52) and are involved in a variety of cellular processes including cytokinesis, vesicle trafficking, cytoskeleton organization, polarity, and formation of diffusion barriers (35,39,44,53,62). Perhaps, not surprisingly given their roles in such critical processes, septin defects have been associated with many human diseases (29).The septins were first discovered in the budding yeast Saccharomyces cerevisiae as temperature-sensitive cell cycle mutants defective in cytokinesis (31, 41). Early in the yeast cell cycle, septins localize as a cap at the future site of bud emergence. As the bud emerges, septins localize first as a ring at the mother/bud neck and later as an hourglass structure as the bud develops (25,26,37). At cytokinesis, the hourglass structure converts into two rings. Septins at the neck form diffusion barriers that keep the cellular machinery necessary for growth and cytokinesis properly localized (16,18,22,49,50,60). In addition, septins are part of the morphogenesis checkpoint that coordinates nuclear division with bud formation (37).In S. cerevisiae septins organize into hetero-oligomeric octamers that associate end to end to form nonpolar filaments (6). Electron ...

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Section: Discussionmentioning

confidence: 99%

The Septin AspB in Aspergillus nidulans Forms Bars and Filaments and Plays Roles in Growth Emergence and Conidiation

2012

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“…Septin 12 and 14 were significantly expressed in testis which belongs to a family of polymerizing guanosine 5Ј-triphosphate (GTP)-binding proteins that are required for many cellular functions, such as membrane compartmentalaization, vesicular trafficking, mitosis and cytoskeletal remodeling, 20) for example, septin12 is critical for The overlap of human (317), mouse (449) and rat (147) testis-specific genes are shown. The information of common genes in the three group are shown in Table 4.…”

Section: Unigenementioning

confidence: 99%

Comparative and Functional Analysis of Testis-Specific Genes

Liu¹,

Jin²,

Li³

et al. 2011

Biological & Pharmaceutical Bulletin

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The testis is the special male gonad responsible for spermatogenesis and steroidogenesis with complex gene expressions. Characterizing and comparing the testis-specific genes in different species can reveal key genes related to testis specifical functions and provide supplementary information for study of human testis function. We screened testis-specific genes from Unigene libraries, total 317, 449 and 147 testis-specific genes were identified for human, mouse and rat, respectively. Ten from thirteen selected human testis-specific genes were validated exclusively expressed in the testis by reverse transcription polymerase chain reaction (RT-PCR). Systematic bioinformatics analysis showed that specific genes were mainly related to spermatogenesis and testis development process with significant Glycolysis and Pyruvate metabolism. Enrichment functions were discussed.Key words testis; specific; digital differential display Biol. Pharm. Bull. 34(1) 28-35 (2011) © 2011 Pharmaceutical Society of Japan * To whom correspondence should be addressed. e-mail: zxsys008@126.com Colon 7 29584 1 5219 3 5458 Heart 4 19926 8 67542 4 31600 Kidney 6 49568 10 54164 4 24601 Liver 11 72628 6 25033 3 59093 Lung 7 46559 7 40355 2 8065 Muscle 2 6424 2 3031 1 2429 Ovary 4 10862 2 6847 1 4443 Pancreas 1 4308 6 22020 1 16173 Placenta 12 71806 7 21182 2 8475 Prostate 5 63083 0 0 1 9076 Spleen 2 36689 3 46301 1 3629 Stomach 11 36759 4 18360 0 0 Thymus 4 72916 8 93976 0 0 Uterus 5 58541 0 0 0 0 Total 96 783531 74 454582 30 198862 Libraries from 18 organs against testis libraries were used in the digital differential display (DDD) program.

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“…Second, septin rings function as a diffusion barrier across the plane of the mother-bud neck (Caudron and Barral, 2009). To date, 14 mammalian septin genes (SEPT1-14) have been identified (Cao et al, 2009;McMurray and Thorner, 2009). As protein scaffolds and diffusion barriers, septins have conserved their key roles in cell polarity and cell-cycle progression (Gladfelter et al, 2001;Kinoshita, 2006;Longtine and Bi, 2003;McMurray and Thorner, 2009;Park et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Septin 6 Regulates the Cytoarchitecture of Neurons through Localization at Dendritic Branch Points and Bases of Protrusions

Cho

Lee

Dutta

et al. 2011

Molecules and Cells

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*Septins, a conserved family of GTP-binding proteins with a conserved role in cytokinesis, are present in eukaryotes ranging from yeast to mammals. Septins are also highly expressed in neurons, which are post-mitotic cells. Septin6 (SEPT6) forms SEPT2/6/7 complexes in vivo. In this study, we produced a very specific SEPT6 antibody. Immunocytochemisty (ICC) of dissociated hippocampal cultures revealed that SEPT6 was highly expressed in neurons. Developmentally, the expression of SEPT6 was very low until stage 3 (axonal outgrowth). Significant expression of SEPT6 began at stage 4 (outgrowth of dendrites). At this stage, SEPT6 clusters were positioned at the branch points of developing dendrites. In maturing and mature neurons (stage 5), SEPT6 clusters were positioned at the base of filopodia and spines, and pre-synaptic boutons. Detergent extraction experiments also indicated that SEPT6 is not a post-synaptic density (PSD) protein. Throughout morphologic development of neurons, SEPT6 always formed tiny rings (external diameter, ~0.5 µm), which appear to be clusters at low magnification. When a Sept6 RNAi vector was introduced at the early developmental stage (DIV 2), a significant reduction in dendritic length and branch number was evident. Taken together, our results indicate that SEPT6 begins to be expressed at the stage of dendritic outgrowth and regulates the cytoarchitecture.

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The evolution, complex structures and function of septin proteins

Cited by 64 publications

References 137 publications

The Septin AspB in Aspergillus nidulans Forms Bars and Filaments and Plays Roles in Growth Emergence and Conidiation

The Septin AspB in Aspergillus nidulans Forms Bars and Filaments and Plays Roles in Growth Emergence and Conidiation

Comparative and Functional Analysis of Testis-Specific Genes

Septin 6 Regulates the Cytoarchitecture of Neurons through Localization at Dendritic Branch Points and Bases of Protrusions

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