Increased Chitin Synthesis in Response to Type II Myosin Deficiency in Saccharomyces cerevisiae

2000 ◽  
Vol 3 (1) ◽  
pp. 20-25 ◽  
Author(s):  
J.A. Cruz ◽  
R. Garcia ◽  
J.F. Rodriguez-Orengo ◽  
J.R. Rodriguez-Medina
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Type Ii ◽  
Chitin Synthesis ◽  
Type Ii Myosin

scholarly journals Role of the Hof1–Cyk3 interaction in cleavage-furrow ingression and primary-septum formation during yeast cytokinesis

2018 ◽  
Vol 29 (5) ◽  
pp. 597-609 ◽  
Author(s):  
Meng Wang ◽  
Ryuichi Nishihama ◽  
Masayuki Onishi ◽  
John R. Pringle
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Functional Significance ◽  
Normal Rate ◽  
Cleavage Furrow ◽  
Type Ii ◽  
Septum Formation ◽  
Primary Septum ◽  
Direct Binding ◽  
Type Ii Myosin

In Saccharomyces cerevisiae, it is well established that Hof1, Cyk3, and Inn1 contribute to septum formation and cytokinesis. Because hof1∆ and cyk3∆ single mutants have relatively mild defects but hof1∆ cyk3∆ double mutants are nearly dead, it has been hypothesized that these proteins contribute to parallel pathways. However, there is also evidence that they interact physically. In this study, we examined this interaction and its functional significance in detail. Our data indicate that the interaction 1) is mediated by a direct binding of the Hof1 SH3 domain to a proline-rich motif in Cyk3; 2) occurs specifically at the time of cytokinesis but is independent of the (hyper)phosphorylation of both proteins that occurs at about the same time; 3) is dispensable for the normal localization of both proteins; 4) is essential for normal primary-septum formation and a normal rate of cleavage-furrow ingression; and 5) becomes critical for growth when either Inn1 or the type II myosin Myo1 (a key component of the contractile actomyosin ring) is absent. The similarity in phenotype between cyk3∆ mutants and mutants specifically lacking the Hof1–Cyk3 interaction suggests that the interaction is particularly important for Cyk3 function, but it may be important for Hof1 function as well.

scholarly journals Identification and functional analysis of the essential and regulatory light chains of the only type II myosin Myo1p in Saccharomyces cerevisiae

2004 ◽  
Vol 165 (6) ◽  
pp. 843-855 ◽  
Author(s):  
Jianying Luo ◽  
Elizabeth A. Vallen ◽  
Christopher Dravis ◽  
Serguei E. Tcheperegine ◽  
Becky Drees ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Point Mutation ◽  
Light Chain ◽  
Type Ii ◽  
Actin Ring ◽  
Major Function ◽  
Regulatory Light Chains ◽  
Essential Light Chain ◽  
Type V ◽  
Type Ii Myosin

Cytokinesis in Saccharomyces cerevisiae involves coordination between actomyosin ring contraction and septum formation and/or targeted membrane deposition. We show that Mlc1p, a light chain for Myo2p (type V myosin) and Iqg1p (IQGAP), is the essential light chain for Myo1p, the only type II myosin in S. cerevisiae. However, disruption or reduction of Mlc1p–Myo1p interaction by deleting the Mlc1p binding site on Myo1p or by a point mutation in MLC1, mlc1-93, did not cause any obvious defect in cytokinesis. In contrast, a different point mutation, mlc1-11, displayed defects in cytokinesis and in interactions with Myo2p and Iqg1p. These data suggest that the major function of the Mlc1p–Myo1p interaction is not to regulate Myo1p activity but that Mlc1p may interact with Myo1p, Iqg1p, and Myo2p to coordinate actin ring formation and targeted membrane deposition during cytokinesis. We also identify Mlc2p as the regulatory light chain for Myo1p and demonstrate its role in Myo1p ring disassembly, a function likely conserved among eukaryotes.

scholarly journals Chs1p and Chs3p, two proteins involved in chitin synthesis, populate a compartment of the Saccharomyces cerevisiae endocytic pathway.

1996 ◽  
Vol 7 (12) ◽  
pp. 1909-1919 ◽  
Author(s):  
M Ziman ◽  
J S Chuang ◽  
R W Schekman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Endocytic Pathway ◽  
Chitin Synthase ◽  
Cell Fractionation ◽  
Cell Wall Polysaccharide ◽  
Chitin Synthesis ◽  
A Cell ◽  
Steady State Levels ◽  
Membrane Bound

In Saccharomyces cerevisiae, the synthesis of chitin, a cell-wall polysaccharide, is temporally and spatially regulated with respect to the cell cycle and morphogenesis. Using immunological reagents, we found that steady-state levels of Chs1p and Chs3p, two chitin synthase enzymes, did not fluctuate during the cell cycle, indicating that they are not simply regulated by synthesis and degradation. Previous cell fractionation studies demonstrated that chitin synthase I activity (CSI) exists in a plasma membrane form and in intracellular membrane-bound particles called chitosomes. Chitosomes were proposed to act as a reservoir for regulated transport of chitin synthase enzymes to the division septum. We found that Chs1p and Chs3p resided partly in chitosomes and that this distribution was not cell cycle regulated. Pulse-chase cell fractionation experiments showed that chitosome production was blocked in an endocytosis mutant (end4-1), indicating that endocytosis is required for the formation or maintenance of chitosomes. Additionally, Ste2p, internalized by ligand-induced endocytosis, cofractionated with chitosomes, suggesting that these membrane proteins populate the same endosomal compartment. However, in contrast to Ste2p, Chs1p and Chs3p were not rapidly degraded, thus raising the possibility that the temporal and spatial regulation of chitin synthesis is mediated by the mobilization of an endosomal pool of chitin synthase enzymes.

scholarly journals F-actin and a Type-II Myosin Are Required for Efficient Clustering of the ER Stress Sensor Ire1

2013 ◽  
Vol 38 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Yuki Ishiwata-Kimata ◽  
Yo-hei Yamamoto ◽  
Ken Takizawa ◽  
Kenji Kohno ◽  
Yukio Kimata
Keyword(s):  
Er Stress ◽  
Type Ii ◽  
Stress Sensor ◽  
Type Ii Myosin

scholarly journals Isolation and characterization of a Type II casein kinase (‘casein kinase-TS’) from Saccharomyces cerevisiae

FEBS Letters ◽  
1982 ◽  
Vol 144 (2) ◽  
pp. 354-358 ◽  
Author(s):  
Maria Pia Rigobello ◽  
Elisabetta Jori ◽  
Giovanna Carignani ◽  
Lorenzo A. Pinna
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Casein Kinase ◽  
Type Ii ◽  
Isolation And Characterization

scholarly journals Saccharomyces cerevisiae contains a Type II phosphoinositide 4-kinase

2003 ◽  
Vol 371 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Shary N. SHELTON ◽  
Barbara BARYLKO ◽  
Derk D. BINNS ◽  
Bruce F. HORAZDOVSKY ◽  
Joseph P. ALBANESI ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fluorescent Protein ◽  
Distinct Type ◽  
Type Ii ◽  
Yeast Saccharomyces Cerevisiae ◽  
Molar Ratios ◽  
Ionic Detergent ◽  
Km Value ◽  
Green Fluorescent ◽  
Vacuolar Membranes

The yeast Saccharomyces cerevisiae contains two known phosphoinositide 4-kinases (PI 4-kinases), which are encoded by PIK1 and STT4; both are essential. Pik1p is important for exocytic transport from the Golgi, whereas Stt4p plays a role in cell-wall integrity and cytoskeletal rearrangements. In the present study, we report that cells have a third PI 4-kinase activity encoded by LSB6, a protein identified previously in a two-hybrid screen as interacting with LAS17p. Although Pik1p and Stt4p are closely related members of the Type III class of PI 4-kinases, Lsb6p belongs to the distinct Type II class, based on its amino acid sequence, its sensitivity to inhibition by adenosine and its insensitivity to wortmannin. Lsb6p is the first fungal Type II enzyme cloned. The protein was expressed and purified from Sf9 cells and used to define kinetic parameters. As commonly observed for surface-active enzymes, activities varied both with substrate concentration and lipid/detergent molar ratios. Maximal activities of approx. 100min−1 were obtained at the PI/Triton X-100 ratio of 1:5. The Km value for ATP was 266μM, intermediate between the values reported for mammalian Type II and III kinases. Epitope-tagged protein, expressed in yeast, was entirely particulate, and about half of it could be extracted with non-ionic detergent. Lsb6p–green fluorescent protein was found both on vacuolar membranes and on the plasma membrane, suggesting a role in endocytic or exocytic pathways.

scholarly journals Identification of a Novel Mycobacterial 3-Hydroxyacyl-Thioester Dehydratase, HtdZ (Rv0130), by Functional Complementation in Yeast

2008 ◽  
Vol 190 (11) ◽  
pp. 4088-4090 ◽  
Author(s):  
Aner Gurvitz ◽  
J. Kalervo Hiltunen ◽  
Alexander J. Kastaniotis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mycobacterium Tuberculosis ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
De Novo ◽  
Acid Synthesis ◽  
Functional Complementation ◽  
Type Ii ◽  
Mutant Cells ◽  
Dehydratase Activity

ABSTRACT We report on the identification of Mycobacterium tuberculosis HtdZ (Rv0130), representing a novel 3-hydroxyacyl-thioester dehydratase. HtdZ was picked up by the functional complementation of Saccharomyces cerevisiae htd2Δ cells lacking the dehydratase of mitochondrial type II fatty acid synthase. Mutant cells expressing HtdZ contained dehydratase activity, recovered their respiratory ability, and partially restored de novo lipoic acid synthesis.

A Type II Myosin ATPase Inhibitor Reduces Contractionstimulated Glucose Transport in Rat Skeletal Muscle

2008 ◽  
Vol 40 (Supplement) ◽  
pp. S37
Author(s):  
David R. Blair ◽  
Edward B. Arias ◽  
Katsuhiko Funai ◽  
Gregory D. Cartee
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
Myosin Atpase ◽  
Type Ii ◽  
Rat Skeletal Muscle ◽  
Atpase Inhibitor ◽  
Type Ii Myosin

scholarly journals Aim44p regulates phosphorylation of Hof1p to promote contractile ring closure during cytokinesis in budding yeast

2014 ◽  
Vol 25 (6) ◽  
pp. 753-762 ◽  
Author(s):  
Dana M. Alessi Wolken ◽  
Joseph McInnes ◽  
Liza A. Pon
Keyword(s):  
Cell Division ◽  
Protein Product ◽  
Ring Closure ◽  
Type Ii ◽  
Contractile Ring ◽  
Double Ring ◽  
Mother And Daughter ◽  
Associated Proteins ◽  
And Function ◽  
Type Ii Myosin

Whereas actomyosin and septin ring organization and function in cytokinesis are thoroughly described, little is known regarding the mechanisms by which the actomyosin ring interacts with septins and associated proteins to coordinate cell division. Here we show that the protein product of YPL158C, Aim44p, undergoes septin-dependent recruitment to the site of cell division. Aim44p colocalizes with Myo1p, the type II myosin of the contractile ring, throughout most of the cell cycle. The Aim44p ring does not contract when the actomyosin ring closes. Instead, it forms a double ring that associates with septin rings on mother and daughter cells after cell separation. Deletion of AIM44 results in defects in contractile ring closure. Aim44p coimmunoprecipitates with Hof1p, a conserved F-BAR protein that binds both septins and type II myosins and promotes contractile ring closure. Deletion of AIM44 results in a delay in Hof1p phosphorylation and altered Hof1p localization. Finally, overexpression of Dbf2p, a kinase that phosphorylates Hof1p and is required for relocalization of Hof1p from septin rings to the contractile ring and for Hof1p-triggered contractile ring closure, rescues the cytokinesis defect observed in aim44∆ cells. Our studies reveal a novel role for Aim44p in regulating contractile ring closure through effects on Hof1p.

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