Dynamic changes in the distribution of cytoplasmic myosin during Drosophila embryogenesis

Development ◽  
1991 ◽  
Vol 111 (1) ◽  
pp. 1-14 ◽  
Author(s):  
P.E. Young ◽  
T.C. Pesacreta ◽  
D.P. Kiehart
Keyword(s):  
Plasma Membrane ◽  
Immune Serum ◽  
Early Embryogenesis ◽  
Preimmune Serum ◽  
Dynamic Changes ◽  
Somatic Nucleus ◽  
Drosophila Embryogenesis ◽  
Muscle Myosin ◽  
Blastoderm Stage ◽  
Egg Cortex

Dramatic changes in the localization of conventional non-muscle myosin characterize early embryogenesis in Drosophila melanogaster. During cellularization, myosin is concentrated around the furrow canals that form the leading margin of the plasma membrane as it plunges inward to package each somatic nucleus into a columnar epithelial cell. During gastrulation, there is specific anti-myosin staining at the apical ends of those cells that change shape in regions of invagination. Both of these localizations appear to result from a redistribution of a cortical store of maternal myosin. In the preblastoderm embryo, myosin is localized to the egg cortex, sub-cortical arrays of inclusions, and, diffusely, the yolk-free periplasm. At the syncytial blastoderm stage, myosin is found within cytoskeletal caps associated with the somatic nuclei at the embryonic surface. Following the final syncytial division, these myosin caps give rise to the myosin rings observed during cellularization. These distributions are observed with both whole immune serum and affinity-purified antibodies directed against Drosophila non-muscle myosin heavy chain. They are not detected in embryos stained with anti-Drosophila muscle myosin antiserum or with preimmune serum. Although immunolocalization can only suggest possible function, these myosin localizations and the coincident changes in cell morphology are consistent with a key role for non-muscle myosin in powering cellularization and gastrulation during embryogenesis.

scholarly journals Dynamic accumulation of a helper NLR at the plant-pathogen interface underpins pathogen recognition

2021 ◽  
Author(s):  
Cian Duggan ◽  
Eleonora Moratto ◽  
Zachary Savage ◽  
Eranthika Hamilton ◽  
Hiroaki Adachi ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Immune Responses ◽  
Subcellular Localization ◽  
Plant Pathogen ◽  
Coiled Coil ◽  
Dynamic Changes ◽  
Pathogen Effectors ◽  
Mediate Response ◽  
Potato Famine ◽  
Irish Potato Famine

Plants employ sensor-helper pairs of NLR immune receptors to recognize pathogen effectors and activate immune responses. Yet the subcellular localization of NLRs pre- and post- activation during pathogen infection remains poorly known. Here we show that NRC4, from the 'NRC' solanaceous helper NLR family, undergoes dynamic changes in subcellular localization by shuttling to and from the plant-pathogen haustorium interface established during infection by the Irish potato famine pathogen Phytophthora infestans. Specifically, prior to activation, NRC4 accumulates at the extra-haustorial membrane (EHM), presumably to mediate response to perihaustorial effectors, that are recognized by NRC4-dependent sensor NLRs. However not all NLRs accumulate at the EHM, as the closely related helper NRC2, and the distantly related ZAR1, did not accumulate at the EHM. NRC4 required an intact N- terminal coiled coil domain to accumulate at the EHM, whereas the functionally conserved MADA motif implicated in cell death activation and membrane insertion was dispensable for this process. Strikingly, a constitutively autoactive NRC4 mutant did not accumulate at the EHM and showed punctate distribution that mainly associated with the plasma membrane, suggesting that post-activation, NRC4 probably undergoes a conformation switch to form clusters that do not preferentially associate with the EHM. When NRC4 is activated by a sensor NLR during infection however, NRC4 formed puncta mainly at the EHM and to a lesser extent at the plasma membrane. We conclude that following activation at the EHM, NRC4 may spread to other cellular membranes from its primary site of activation to trigger immune responses.

Ultrastructural Evidence for Myosin of the Smooth Muscle Type at the Surface of Trypsin-Dissociated Embryonic Chick Cells

1974 ◽  
Vol 15 (2) ◽  
pp. 279-289
Author(s):  
I. AP GWYNN ◽  
R. B. KEMP ◽  
B. M. JONES ◽  
U. GRÖSCHEL-STEWART
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Striated Muscle ◽  
Smooth Muscle Myosin ◽  
Rabbit Serum ◽  
Embryonic Chick ◽  
Antibody Preparation ◽  
Rabbit Igg ◽  
Antibody Conjugate ◽  
Muscle Myosin

Cells dissociated from embryonic chick muscle tissue using trypsin were rotated in the presence of globulin-enriched rabbit antisera against both smooth and striated muscle actomyosins originating from chicken gizzard (GAM) and pectoralis (PAM) muscles respectively. The presence of the rabbit antibodies was demonstrated using peroxidase-labelled sheep anti-rabbit λ-globulins, the enzyme-antibody conjugate being located by electron-microscope histochemistry. Anti-GAM λ-globulins reacted strongly with the plasma membrane. Judging from the complete absence of staining, λ-globulins from non-immunized rabbit serum did not interact with the membrane.When λ-globulins of sheep anti-rabbit IgG serum were applied alone, that is in the absence of pretreatment with rabbit λ-globulin, there was an observable reaction with the cell surface. Preincubation of anti-GAM with the heavy meromyosin fraction from smooth-muscle myosin inhibited the interaction of the antibodies with the membrane, as evidenced by the absence of staining. A weak positive reaction obtained with anti-PAM was due to components of the antibody preparation which were reactive with actin and not with PAM. It was concluded that a smooth-muscle myosin-like protein is an integral part of the plasma membrane of embryonic chick muscle cells.

scholarly journals Immunohistochemical localization in normal tissues of different epitopes in the multidrug transport protein P170: evidence for localization in brain capillaries and crossreactivity of one antibody with a muscle protein.

1989 ◽  
Vol 37 (2) ◽  
pp. 159-164 ◽  
Author(s):  
F Thiebaut ◽  
T Tsuruo ◽  
H Hamada ◽  
M M Gottesman ◽  
I Pastan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Cardiac Muscle ◽  
Muscle Fibers ◽  
Transport Protein ◽  
Rat Tissues ◽  
Human Tissues ◽  
Normal Tissues ◽  
Skeletal Muscle Fibers ◽  
Muscle Myosin

Using peroxidase immunohistochemistry, we examined the distribution of P170, a multidrug transport protein, in normal tissues by use of two different monoclonal antibodies (MAb). MAb MRK16 is a MAb that has been shown to react with an epitope in P170 located on the external face of the plasma membrane of multidrug-resistant human cells. MAb C219 has been shown to react with P170 in many mammalian species, and detects an epitope located on the cytoplasmic face of the plasma membrane. Using MRK16, we have previously described the localization of P170 on the bile canalicular face of hepatocytes, the apical surface of proximal tubular cells in kidney, and the surface epithelium in the lower GI tract in normal human tissues. In this work, we report that MRK16 also detects P170 in the capillaries of some human brain samples. A similar pattern was found using MAb C219 in rat tissues. in addition, MAb C219 showed intense localization in selected skeletal muscle fibers and all cardiac muscle fibers in rat and human tissues. ATPase cytochemistry showed that these reactive skeletal muscle fibers were of the type I (slow-twitch) class. Other additional sites of C219 reactivity in rat tissues were found in pancreatic acini, seminal vesicle, and testis. Electrophoretic gel immunoblotting showed two protein bands reactive with MAb C219. In liver, MAb C219 reacted with a approximately 170 KD band. In skeletal and cardiac muscle, MAb C219 reacted with a approximately 200 KD band which migrated in the same position as myosin. This band also reacted with an antibody to skeletal muscle myosin. This result suggests that C219 may crossreact with the heavy chain of muscle myosin in cardiac and skeletal muscle. Because MAb C219 reacts with proteins other than P170, it should be used with caution in studies of multidrug resistance.

scholarly journals Calcium Signaling Regulates Trafficking of Familial Hypocalciuric Hypercalcemia (FHH) Mutants of the Calcium Sensing Receptor

2012 ◽  
Vol 26 (12) ◽  
pp. 2081-2091 ◽  
Author(s):  
Michael P. Grant ◽  
Ann Stepanchick ◽  
Gerda E. Breitwieser
Keyword(s):  
Plasma Membrane ◽  
Steady State ◽  
State Level ◽  
Membrane Targeting ◽  
Familial Hypocalciuric Hypercalcemia ◽  
Loss Of Function ◽  
Wild Type ◽  
Calcium Sensing Receptor ◽  
Dynamic Changes ◽  
Calcium Sensing

Abstract Calcium-sensing receptors (CaSRs) regulate systemic Ca2+ homeostasis. Loss-of-function mutations cause familial benign hypocalciuric hypercalcemia (FHH) or neonatal severe hyperparathyroidism (NSHPT). FHH/NSHPT mutations can reduce trafficking of CaSRs to the plasma membrane. CaSR signaling is potentiated by agonist-driven anterograde CaSR trafficking, leading to a new steady state level of plasma membrane CaSR, which is maintained, with minimal functional desensitization, as long as extracellular Ca2+ is elevated. This requirement for CaSR signaling to drive CaSR trafficking to the plasma membrane led us to reconsider the mechanism(s) contributing to dysregulated trafficking of FHH/NSHPT mutants. We simultaneously monitored dynamic changes in plasma membrane levels of CaSR and intracellular Ca2+, using a chimeric CaSR construct, which allowed explicit tracking of plasma membrane levels of mutant or wild-type CaSRs in the presence of nonchimeric partners. Expression of mutants alone revealed severe defects in plasma membrane targeting and Ca2+ signaling, which were substantially rescued by coexpression with wild-type CaSR. Biasing toward heterodimerization of wild-type and FHH/NSHPT mutants revealed that intracellular Ca2+ oscillations were insufficient to rescue plasma membrane targeting. Coexpression of the nonfunctional mutant E297K with the truncation CaSRΔ868 robustly rescued trafficking and Ca2+ signaling, whereas coexpression of distinct FHH/NSHPT mutants rescued neither trafficking nor signaling. Our study suggests that rescue of FHH/NSHPT mutants requires a steady state intracellular Ca2+ response when extracellular Ca2+ is elevated and argues that Ca2+ signaling by wild-type CaSRs rescues FHH mutant trafficking to the plasma membrane.

Oocyte activation in invertebrates and humans

Zygote ◽  
1994 ◽  
Vol 2 (4) ◽  
pp. 373-377 ◽  
Author(s):  
Brain Dale
Keyword(s):  
Plasma Membrane ◽  
Metabolic Activity ◽  
Second Messengers ◽  
Second Messenger ◽  
Early Embryogenesis ◽  
Oocyte Activation ◽  
Sperm Binding ◽  
Messenger System ◽  
Oocyte Cytoplasm

Oocytes are metabolically repressed cells that, in most cases, require a signal from the fertilising spermatozoon to trigger activation. Physiological competence of the activated oocyte, a prerequisite for early embryogenesis, depends, therefore, not only on the quality of the oocyte, but also on the quality of the spermatozoon (Dale, 1983; Tosti & Dale, 1992). There are two current opinions as to how the spermatozoon triggers the oocyte into metabolic activity (Dale & DeFelice, 1990). The first hypothesis is that following gamete fusion the spermatozoon releases a soluble activating factor into the oocyte cytoplasm that is then amplified globally by second messengers in the oocyte. The second is that sperm binding to receptors spanning the oocyte plasma membrane is the signal that is transduced to the second messenger system of the oocyte (Swann, 1993; Foltz & Shilling, 1993).

scholarly journals Dynamic changes in the association between maternal mRNAs and endoplasmic reticulum during ascidian early embryogenesis

2021 ◽  
Author(s):  
Toshiyuki Goto ◽  
Shuhei Torii ◽  
Aoi Kondo ◽  
Junji Kawakami ◽  
Haruka Yagi ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Translational Regulation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Early Embryogenesis ◽  
Axis Formation ◽  
Second Phase ◽  
Dynamic Changes ◽  
Maternal Mrna ◽  
Maternal Mrnas

AbstractAxis formation is one of the most important events occurring at the beginning of animal development. In the ascidian egg, the antero-posterior axis is established at this time owing to a dynamic cytoplasmic movement called cytoplasmic and cortical reorganisation. During this movement, mitochondria, endoplasmic reticulum (ER), and maternal mRNAs (postplasmic/PEM RNAs) are translocated to the future posterior side. Although accumulating evidence indicates the crucial roles played by the asymmetrical localisation of these organelles and the translational regulation of postplasmic/PEM RNAs, the organisation of ER has not been described in sufficient detail to date owing to technical difficulties. In this study, we developed three different multiple staining protocols for visualising the ER in combination with mitochondria, microtubules, or mRNAs in whole-mount specimens. We defined the internally expanded “dense ER” using these protocols and described cisterna-like structures of the dense ER using focused ion beam-scanning electron microscopy. Most importantly, we described the dynamic changes in the colocalisation of postplasmic/PEM mRNAs and dense ER; for example, macho-1 mRNA was detached and excluded from the dense ER during the second phase of ooplasmic movements. These detailed descriptions of the association between maternal mRNA and ER can provide clues for understanding the translational regulation mechanisms underlying axis determination during ascidian early embryogenesis.

scholarly journals A novel coordinated function of Myosin II with GOLPH3 controls centralspindlin localization during cytokinesis in Drosophila

2020 ◽  
Vol 133 (21) ◽  
pp. jcs252965
Author(s):  
Stefano Sechi ◽  
Anna Frappaolo ◽  
Angela Karimpour-Ghahnavieh ◽  
Roberta Fraschini ◽  
Maria Grazia Giansanti
Keyword(s):  
Plasma Membrane ◽  
Heavy Chain ◽  
Light Chain ◽  
Animal Cell ◽  
Myosin Ii ◽  
Contractile Ring ◽  
Ring Assembly ◽  
Missense Allele ◽  
Phosphatidylinositol 4 ◽  
Muscle Myosin

ABSTRACTIn animal cell cytokinesis, interaction of non-muscle myosin II (NMII) with F-actin provides the dominant force for pinching the mother cell into two daughters. Here we demonstrate that celibe (cbe) is a missense allele of zipper, which encodes the Drosophila Myosin heavy chain. Mutation of cbe impairs binding of Zipper protein to the regulatory light chain Spaghetti squash (Sqh). In dividing spermatocytes from cbe males, Sqh fails to concentrate at the equatorial cortex, resulting in thin actomyosin rings that are unable to constrict. We show that cbe mutation impairs localization of the phosphatidylinositol 4-phosphate [PI(4)P]-binding protein Golgi phosphoprotein 3 (GOLPH3, also known as Sauron) and maintenance of centralspindlin at the cell equator of telophase cells. Our results further demonstrate that GOLPH3 protein associates with Sqh and directly binds the centralspindlin subunit Pavarotti. We propose that during cytokinesis, the reciprocal dependence between Myosin and PI(4)P–GOLPH3 regulates centralspindlin stabilization at the invaginating plasma membrane and contractile ring assembly.

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