scholarly journals The unconventional myosin encoded by the myoA gene plays a role in Dictyostelium motility.

1993 ◽  
Vol 4 (2) ◽  
pp. 233-246 ◽  
Author(s):  
M A Titus ◽  
D Wessels ◽  
J A Spudich ◽  
D Soll
Keyword(s):  
Cyclic Amp ◽  
Gene Targeting ◽  
Gene Product ◽  
The Other ◽  
Computer Assisted ◽  
Spatial Gradient ◽  
Unconventional Myosin ◽  
Cellular Translocation ◽  
Src Homology 3 ◽  
Src Homology

The myoA gene of Dictyostelium is a member of a gene family of unconventional myosins. The myosin Is share homologous head and basic domains, but the myoA gene product lacks the glycine-, proline-, alanine-rich and src homology 3 domains typical of several of the other myosin Is. A mutant strain of Dictyostelium lacking a functional myoA gene was produced by gene targeting, and the motility of this strain in buffer and a spatial gradient of the chemoattractant cyclic AMP was analyzed by computer-assisted methods. The myoA- cells have a normal elongate morphology in buffer but exhibit a decrease in the instantaneous velocity of cellular translocation, an increase in the frequency of lateral pseudopod formation, and an increase in turning. In a spatial gradient, in which the frequency of pseudopod formation is depressed, myoA- cells exhibit positive chemotaxis but still turn several times more frequently than control cells. These results demonstrate that the other members of the unconventional myosin family do not fully compensate for the loss of functional myoA gene product. Surprisingly, the phenotype of the myoA- strain closely resembles that of the myoB- strain, suggesting that both play a role in the frequency of pseudopod formation and turning during cellular translocation.

The regulation of chemotaxis and chemokinesis in Dictyostelium amoebae by temporal signals and spatial gradients of cyclic AMP

1994 ◽  
Vol 107 (2) ◽  
pp. 659-667 ◽  
Author(s):  
M.G. Vicker
Keyword(s):  
Cyclic Amp ◽  
Molecular Diffusion ◽  
Gradient Field ◽  
Computer Assisted ◽  
Spatial Gradient ◽  
Spatial Gradients ◽  
Cell Accumulation ◽  
Initial Effect ◽  
Gradient Orientation ◽  
Infusion System

The tactic and kinetic locomotion of Dictyostelium discoideum amoebae were examined in cyclic AMP (cAMP) spatial gradient and temporal signal fields. The distributions of migrating cells were examined within 150 microns-thick micropore filters after incubation with different cAMP concentrations, [cAMP], applied in three ways across the fields: as positively or negatively developing gradients, generated either by increasing or decreasing the [cAMP] on one side of the filter, respectively, or as static, linear gradients after negative development. Chemotaxis was only induced by oriented, temporally increasing [cAMP]. Pulses propagated by molecular diffusion or mechanical flow were equally effective. Negatively developing cAMP gradients had no initial effect on cell accumulation. However, if the subsequent static spatial gradient was maintained by an infusion system, some gradients also induced cell accumulation, whose degree and direction depended on the gradient [cAMP]. The basis of this new effect was examined by tracking individual cells by computer-assisted videomicroscopy during locomotion in different [cAMP]. Cells produced a triphasic [cAMP]-dependent response, with optimal cell motility induced by 10–30 nM. The results demonstrate that cell accumulation either up-field or down-field in spatial gradients is governed by the field locations of the attractant concentrations that induce the relative locomotory maxima and minima in the gradient field. Cells perceive the ambient [cAMP], but cannot read the spatial gradient orientation in static or yet steeper regions of developing gradients. Accumulation in static spatial gradients is a function of klino- and orthokinesis, but chemotaxis requires an oriented cAMP pulse or impulse.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of C6-Volatiles on Bioluminescent Plant Pathogens

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 557d-557
Author(s):  
Jennifer Warr ◽  
Fenny Dane ◽  
Bob Ebel
Keyword(s):  
Biological Activity ◽  
Bacterial Growth ◽  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Genetically Engineered ◽  
The Other ◽  
Computer Assisted ◽  
Signal Molecules ◽  
Low Concentrations

C6 volatile compounds are known to be produced by the plant upon pathogen attack or other stress-related events. The biological activity of many of these substances is poorly understood, but some might produce signal molecules important in host–pathogen interactions. In this research we explored the possibility that lipid-derived C6 volatiles have a direct effect on bacterial plant pathogens. To this purpose we used a unique tool, a bacterium genetically engineered to bioluminesce. Light-producing genes from a fish-associated bacterium were introduced into Xanthomonas campestris pv. campestris, enabling nondestructive detection of bacteria in vitro and in the plant with special computer-assisted camera equipment. The effects of different C6 volatiles (trans-2 hexanal, trans-2 hexen-1-ol and cis-3 hexenol) on growth of bioluminescent Xanthomonas campestris were investigated. Different volatile concentrations were used. Treatment with trans-2 hexanal appeared bactericidal at low concentrations (1% and 10%), while treatments with the other volatiles were not inhibitive to bacterial growth. The implications of these results with respect to practical use of trans-2 hexanal in pathogen susceptible and resistant plants will be discussed.

scholarly journals Physical association between Src homology 3 elements and the protein product of the c-cbl proto-oncogene

1994 ◽  
Vol 269 (26) ◽  
pp. 17363-17366 ◽  
Author(s):  
O.M. Rivero-Lezcano ◽  
J.H. Sameshima ◽  
A. Marcilla ◽  
K.C. Robbins
Keyword(s):  
Protein Product ◽  
Src Homology 3 ◽  
Physical Association ◽  
Src Homology

scholarly journals Detection of Src homology 3-binding proteins, including paxillin, in normal and v-Src-transformed Balb/c 3T3 cells

1993 ◽  
Vol 268 (20) ◽  
pp. 14956-14963
Author(s):  
Z. Weng ◽  
J.A. Taylor ◽  
C.E. Turner ◽  
J.S. Brugge ◽  
C. Seidel-Dugan
Keyword(s):  
Binding Proteins ◽  
3T3 Cells ◽  
Src Homology 3 ◽  
Src Homology

scholarly journals ANKRD54 preferentially selects Bruton’s Tyrosine Kinase (BTK) from a Human Src-Homology 3 (SH3) domain library

PLoS ONE ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. e0174909 ◽  
Author(s):  
Manuela O. Gustafsson ◽  
Dara K. Mohammad ◽  
Erkko Ylösmäki ◽  
Hyunseok Choi ◽  
Subhash Shrestha ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Sh3 Domain ◽  
Bruton’S Tyrosine Kinase ◽  
Bruton's Tyrosine Kinase ◽  
Src Homology 3 ◽  
Src Homology

MyelStones: the executive roles of myelin basic protein in myelin assembly and destabilization in multiple sclerosis

2015 ◽  
Vol 472 (1) ◽  
pp. 17-32 ◽  
Author(s):  
Kenrick A. Vassall ◽  
Vladimir V. Bamm ◽  
George Harauz
Keyword(s):  
Multiple Sclerosis ◽  
Myelin Basic Protein ◽  
Intrinsically Disordered Proteins ◽  
Basic Protein ◽  
Disordered Proteins ◽  
Post Translational Modifications ◽  
Src Homology 3 ◽  
Intrinsically Disordered ◽  
Src Homology ◽  
Membrane Anchoring

The classic isoforms of myelin basic protein (MBP, 14–21.5 kDa) are essential to formation of the multilamellar myelin sheath of the mammalian central nervous system (CNS). The predominant 18.5-kDa isoform links together the cytosolic surfaces of oligodendrocytes, but additionally participates in cytoskeletal turnover and membrane extension, Fyn-mediated signalling pathways, sequestration of phosphoinositides and maintenance of calcium homoeostasis. All MBP isoforms are intrinsically disordered proteins (IDPs) that interact via molecular recognition fragments (MoRFs), which thereby undergo local disorder-to-order transitions. Their conformations and associations are modulated by environment and by a dynamic barcode of post-translational modifications, particularly phosphorylation by mitogen-activated and other protein kinases and deimination [a hallmark of demyelination in multiple sclerosis (MS)]. The MBPs are thus to myelin what basic histones are to chromatin. Originally thought to be merely structural proteins forming an inert spool, histones are now known to be dynamic entities involved in epigenetic regulation and diseases such as cancer. Analogously, the MBPs are not mere adhesives of compact myelin, but active participants in oligodendrocyte proliferation and in membrane process extension and stabilization during myelinogenesis. A central segment of these proteins is pivotal in membrane-anchoring and SH3 domain (Src homology 3) interaction. We discuss in the present review advances in our understanding of conformational conversions of this classic basic protein upon membrane association, including new thermodynamic analyses of transitions into different structural ensembles and how a shift in the pattern of its post-translational modifications is associated with the pathogenesis and potentially onset of demyelination in MS.

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