scholarly journals Kinesins Have a Dual Function in Organizing Microtubules during Both Tip Growth and Cytokinesis in Physcomitrella patens

2014 ◽  
Vol 26 (3) ◽  
pp. 1256-1266 ◽  
Author(s):  
Yuji Hiwatashi ◽  
Yoshikatsu Sato ◽  
John H. Doonan
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens ◽  
Dual Function

Microtubules and microfilaments in tip growth: evidence that microtubules impose polarity on protonemal growth in Physcomitrella patens

1988 ◽  
Vol 89 (4) ◽  
pp. 533-540 ◽  
Author(s):  
J. H. DOONAN ◽  
D. J. COVE ◽  
C. W. LLOYD
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens ◽  
Cytochalasin D ◽  
Immunofluorescence Study ◽  
Apical Dome ◽  
High Concentrations ◽  
Cytoskeletal Elements ◽  
Drug Studies ◽  
Tip Cells ◽  
Cytoskeletal Drugs

In this study we compare the contributions of Factin and microtubules to tip growth in filamentous cells of the moss Physcomitrella patens. In tip growth, expansion seems to be restricted to the hemispherical apical dome. Cytoskeletal elements have been suspected, from drug studies, to be involved in this but electron microscopy has generally not confirmed the presence of an apical cytoskeleton. However, in a previous immunofluorescence study we reported that microtubules could be seen to focus upon the apical dome in tip cells of the moss P. patens. In the present investigation F-actin has also been detected at the apices of these cells. Anti-cytoskeletal drugs were therefore used to differentiate between the roles of actin filaments and microtubules in tip growth. At high concentrations (30μM), the herbicide cremart de-polymerized microtubules and caused tip swelling. F-actin was still present under such conditions but its fragmentation by cytochalasin D suppressed this herbicide-induced swelling. On its own, cytochalasin D arrested tip growth without causing swollen tips. At lower concentrations, cremart disorganized microtubules rather than causing their complete depolymerization. Under these conditions, new but swollen growing points were initiated along the filament. The addition of taxol to cremart-treated filaments tended to reduce swelling and to re-polarize outgrowth. With particular combinations of these drugs, multiple lateral out-growths were initiated in the vicinity of the nucleus. It is concluded: (1) that F-actin is present at the tips of Physcomitrella caulonemal apical cells; (2) that unfragmented F-actin is necessary for outgrowth; (3) that even disorganized microtubules permit some degree of outgrowth but that an unperturbed distribution of axial microtubules, focussing upon an apex, is essential in order to impose tubular shape and directionality upon expansion.

scholarly journals Systematic survey of the function of ROP regulators and effectors during tip growth in the moss Physcomitrella patens

2018 ◽  
Vol 70 (2) ◽  
pp. 447-457 ◽  
Author(s):  
Carlisle Bascom ◽  
Graham M Burkart ◽  
Darren R Mallett ◽  
Jacquelyn E O’Sullivan ◽  
Alexis J Tomaszewski ◽  
...  
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens ◽  
Systematic Survey

scholarly journals Physcomitrella patens: a model to investigate the role of RAC/ROP GTPase signalling in tip growth

2010 ◽  
Vol 61 (7) ◽  
pp. 1917-1937 ◽  
Author(s):  
D. Magnus Eklund ◽  
Emma M. Svensson ◽  
Benedikt Kost
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens ◽  
Rop Gtpase

scholarly journals Myosin XI Is Essential for Tip Growth in Physcomitrella patens

2010 ◽  
Vol 22 (6) ◽  
pp. 1868-1882 ◽  
Author(s):  
Luis Vidali ◽  
Graham M. Burkart ◽  
Robert C. Augustine ◽  
Erin Kerdavid ◽  
Erkan Tüzel ◽  
...  
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens ◽  
Myosin Xi

scholarly journals Hydroxyproline O ‐arabinosyltransferase mutants oppositely alter tip growth in Arabidopsis thaliana and Physcomitrella patens

2015 ◽  
Vol 85 (2) ◽  
pp. 193-208 ◽  
Author(s):  
Cora A. MacAlister ◽  
Carlos Ortiz‐Ramírez ◽  
Jörg D. Becker ◽  
José A. Feijó ◽  
Zachary B. Lippman
Keyword(s):  
Arabidopsis Thaliana ◽  
Tip Growth ◽  
Physcomitrella Patens

scholarly journals KCH kinesin drives nuclear transport and cytoskeletal coalescence for tip cell growth

2018 ◽  
Author(s):  
Moé Yamada ◽  
Gohta Goshima
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens ◽  
Focal Point ◽  
Nuclear Transport ◽  
Apical Cell ◽  
Cytoplasmic Dynein ◽  
Long Distance ◽  
Long Distance Transport ◽  
Genes Encoding ◽  
Distance Transport

Long-distance transport along microtubules (MTs) is critical for intracellular organisation. In animals, antagonistic motor proteins kinesin (plus end-directed) and dynein (minus end-directed) drive cargo transport. In land plants, however, the identity of motors responsible for transport is poorly understood, as genes encoding cytoplasmic dynein are missing. How other functions of dynein are brought about in plants also remains unknown. Here, we show that a subclass of the kinesin-14 family, KCH—which can also bind actin—drives MT minus end-directed nuclear transport in the moss Physcomitrella patens. When all four KCH genes were deleted, the nucleus was not maintained in the cell centre but was translocated to the apical end of protonemal cells. In the knockout (KO) line, apical cell tip growth was also severely suppressed. KCH was localised on MTs, including at the MT focal point near the tip where MT plus ends coalesced with actin filaments. MT focus was not persistent in KCH KO lines, whereas actin destabilisation also disrupted the focus despite KCH remaining on unfocused MTs. Functions of nuclear transport and tip growth were distinct, as a truncated KCH construct restored nuclear transport activity but not tip growth retardation of the KO line. Thus, our study identified KCH as a long-distance retrograde transporter as well as a cytoskeletal crosslinker, reminiscent of the versatile animal dynein.

scholarly journals The COPII components Sec23 and Sec24 form isoform specific subcomplexes with Sec23D/E and Sec24C/D essential for tip growth

2020 ◽  
Author(s):  
Mingqin Chang ◽  
Shu-Zon Wu ◽  
Jacquelyn E. O’Sullivan ◽  
Magdalena Bezanilla
Keyword(s):  
Plasma Membrane ◽  
Tip Growth ◽  
Physcomitrella Patens ◽  
Gene Families ◽  
Vesicle Traffic ◽  
Genes Encoding ◽  
Er Exit Sites

AbstractCOPII, a coat of proteins that form vesicles on the ER, mediates vesicle traffic from the ER to the Golgi. In contrast to metazoans that have few genes encoding each COPII component, plants have expanded these gene families leading to the hypothesis that plant COPII has functionally diversified. Here, we analyzed the gene families encoding for the Sec23/24 heterodimer in the moss Physcomitrium (Physcomitrella) patens. In P. patens, Sec23 and Sec24 gene families are each comprised of seven genes. We discovered that Sec23D is functionally redundant with Sec23E and together they are essential for protonemal development. Sec23D is critical for secretion to the Golgi and the plasma membrane in tip growing protonemata. Sec23D preferentially associates with Sec24C/D, also essential for protonemata. In contrast, the remaining five Sec23 genes are dispensable for tip growth, but are redundant with Sec23D/E for gametophore formation. While Sec23A/B/C/F/G do not quantitatively affect Golgi secretion in protonemata, they do contribute to secretion to the plasma membrane. Furthermore, the three highly expressed Sec23 genes in protonemata, Sec23B/D/G form morphologically distinct ER exit sites. These data suggest that Sec23D/E form unique ER exit sites contributing to secretion that is essential for tip growing protonemata.

scholarly journals Novel roles of Kinesin-13 and Kinesin-8 during cell growth and division in the moss Physcomitrella patens

2019 ◽  
Author(s):  
Shu Yao Leong ◽  
Tomoya Edzuka ◽  
Gohta Goshima ◽  
Moé Yamada
Keyword(s):  
Cell Growth ◽  
Mitotic Spindle ◽  
Tip Growth ◽  
Physcomitrella Patens ◽  
Microtubule Dynamics ◽  
Chromosome Movement ◽  
Spindle Formation ◽  
Tip Cells ◽  
Null Mutants

AbstractKinesin-13 and -8 are well-known microtubule (MT) depolymerases that regulate MT length and chromosome movement in animal mitosis. While much is unknown about plant Kinesin-8, Arabidopsis and rice Kinesin-13 have been shown to depolymerise MTs in vitro. However, mitotic function of both kinesins has yet to be understood in plants. Here, we generated the complete null mutants in plants of Kinesin-13 and -8 in the moss Physcomitrella patens. Both kinesins were found to be non-essential for viability, but the Kinesin-13 knockout (KO) line had increased mitotic duration and reduced spindle length, whereas the Kinesin-8 KO line did not display obvious mitotic defects. Surprisingly, spindle MT poleward flux, for which Kinesin-13 is responsible for in animals, was retained in the absence of Kinesin-13. Concurrently, MT depolymerase activity of either moss kinesins could not be observed, with MT catastrophe inducing (Kinesin-13) or MT gliding (Kinesin-8) activity observed in vitro. Interestingly, both KO lines showed waviness in their protonema filaments, which correlated with positional instability of the MT foci in their tip cells. Taken together, the results suggest that plant Kinesin-13 and -8 have diverged in both mitotic function and molecular activity, acquiring new roles in regulating MT foci positioning for directed tip-growth.One sentence summaryThis study uncovered the roles of Kinesin-13 and Kinesin-8 in regulating microtubule dynamics for mitotic spindle formation and straight tip cell growth in the moss Physcomitrella patens

scholarly journals Profilin Is Essential for Tip Growth in the Moss Physcomitrella patens

2007 ◽  
Vol 19 (11) ◽  
pp. 3705-3722 ◽  
Author(s):  
Luis Vidali ◽  
Robert C. Augustine ◽  
Ken P. Kleinman ◽  
Magdalena Bezanilla
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens

Tip Growth in the Moss Physcomitrella Patens

2018 ◽  
pp. 143-166
Author(s):  
Magdalena Bezanilla ◽  
Pierre-François Perroud
Keyword(s):  
Tip Growth ◽  
Physcomitrella Patens
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