Wyniki wyszukiwania

1

Involvement of Rac-Cdc42-PAK pathway in cytoskeletal rearrangements

100%

Szczepanowska J.

Acta Biochimica Polonica

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2009

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tom 56

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nr 2

225-234

The p21-activated kinases (PAKs) are serine/threonine protein kinases interacting with small GTPases - Rac and Cdc42. PAKs are found in most eukaryotes and play an evolutionarily conserved role in many cellular processes. Six human PAKs have been identified, and based on homology, they can be classified into two groups. This review focuses specifically on the role of Rac/Cdc42 regulated PAKs in maintaining and remodeling cytoskeletal structure in various organisms. A list of PAKs substrates and binding partners implicated directly and indirectly in cytoskeletal reorganization is presented. Also perturbations of the Rac/Cdc42/PAK pathway leading to tumorigenesis and neurodegenerative diseases are reviewed.

2

Dynamin - A mechanoenzyme scissing membrane vesicles

100%

Wyroba E., Wiejak J.

Cellular and Molecular Biology Letters

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2002

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tom 07

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nr Suppl.

3

The identification and characterization of a new GTP-binding protein [Gbp45] involved in cell proliferation and death related to mitochondrial function

84%

Kira Y., Nishikawa M.

Cellular and Molecular Biology Letters

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2008

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tom 13

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nr 4

570-584

We describe the identification and characterization of a GTP-binding protein with a molecular weight of 45 kD (Gbp45). Gbp45 cDNA was found to overlap with a hypothetical human protein, PTD004, the sequence of which was previously deposited in the databases. The gene for PTD004 was recently found to be one of the ATPases, hOLA1 (human Obg-like ATPase 1). The Gbp45 gene encodes a protein of 396 amino acid residues. Immunocytochemical analysis and examination with GFP-tagged protein revealed that Gbp45 is primarily located in the cytosolic compartment. Immunoblot analysis showed that the Gbp45 protein is strongly expressed in the neuronal tissues and pancreas. T43N and T56N mutations resulted in a loss of Gbp45’s ability to bind to GTP and a loss of GTPase activity. In cultured cells, the transfection of wild-type Gbp45 accelerated cell proliferation, though T43N and T56N mutations induced cell death. Down-regulating Gbp45 expression decreased the cell proliferation rate and increased the rate of cell death induced by the inhibition of mitochondrial electron transport. These findings indicate that Gbp45 plays important roles in cell proliferation and death related to mitochondrial function.

4

The membrane-cytoskeleton interface controls platelet shape change

84%

Hartwig J. H., Barkalow K., Azim A., McGrath J., Tolias K., Carpenter C.

Cellular and Molecular Biology Letters

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1998

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tom 03

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nr 4

Platelets respond to stimuli by rapidly changing from discs into active forms having lamellipodia and filopodia. Actin filament fragmentation and assembly are essential for platelet shape change. Actin assembly is regulated by an intracellular signaling pathway that involves calcium and the activation of small GTPases and phosphatidylinositol kinases (PI-kinases). Polyphosphoinositides (ppIs), the final products of the PI-kinases, directly interact with a special class of actin associated proteins, the barbed end capping proteins, to initiate actin filament assembly in activated cells.

5

Transport functions and physiological significance of 76 kDa Ral-binding GTPase activating protein [RLIP76]

84%

Awasthi S., Sharma R., Yang Y., Singhal S. S., Pikula S., Bandorowicz-Pikula J., Singh S. V., Zimniak P., Awasthi Y. C.

Acta Biochimica Polonica

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2002

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tom 49

|

nr 4

We have recently demonstrated that a previously known Ral-binding GTPase activating protein, RLIP76, can also catalyze ATP-dependent transport of various structurally unrelated xeno- and endobiotics irrespective of their net charge (Awasthi etal., 2000, Biochemistry, 39: 9327). RLIP76 is a non-ATP binding cassette (ABC) protein but it has two ATP-binding sites and shows basal ATPase activity which is stimulated in the presence of its transport substrates (allocrites) such as doxorubicin (DOX) and S-(2,4-dinitrophenyl) glutathione (DNP-SG). Proteoliposomes reconstituted with purified RLIP76 catalyze ATP-dependent, saturable transport of DOX, as well as of glutathione-conjugates including leukotrienes (LTC4) and the GSH-conjugate of 4-hydroxynonenal (GS-HNE). In erythrocytes the majority of transport activity for DOX, GS-HNE, and LTC4 is accounted for by RLIP76. Cells exposed to mild oxidative stress show a rapid and transient induction of RLIP76 resulting in an increased efflux of GS-HNE and acquire resistance to oxidative stress mediated toxicity and apoptosis. Cells transfected with RLIP76 acquire resistance to DOX through increased efflux of the drug suggesting its possible role in the mechanisms of drug-resistance. In this article, we discuss the significance of transport functions of RLIP76 highlighting its role in the defense mechanisms against oxidative injury, and modulation of signaling mechanisms.

6

Rho kinase in the regulation of cell death and survival

84%

Shi J., Wei L.

Archivum Immunologiae et Therapiae Experimentalis

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2007

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tom 55

|

nr 2

7

The GTPase domain of Galphao contributes to the functional interactions of Galphao with the promyelocytic leukemia zinc finger protein

67%

Won J. H., Ghil S. H.

Cellular and Molecular Biology Letters

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2009

|

tom 14

|

nr 1

46-56

Go, one of the most abundant heterotrimeric G proteins in the brain, is classified as a member of the Gi/Go family based on its homology to Gi proteins. Recently, we identified promyelocytic leukemia zinc finger protein (PLZF) as a candidate downstream effector for the alpha subunit of Go (Gαo). Activated Gαo interacts with PLZF and augments its function as a repressor of transcription and cell growth. G protein-coupled receptor-mediated Gαo activation also enhanced PLZF function. In this study, we determined that the GTPase domain of Gαo contributes to Gαo:PLZF interaction. We also showed that the Gαo GTPase domain is important in modulating the function of PLZF. This data indicates that the GTPase domain of Gαo may be necessary for the functional interaction of Gαo with PLZF.

8

Structure of small G proteins and their regulators

67%

Paduch M., Jelen F., Otlewski J.

Acta Biochimica Polonica

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2001

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tom 48

|

nr 4

In recent years small G proteins have become an intensively studied group of regulatory GTP hydrolases involved in cell signaling. More than 100 small G proteins have been identified in eucaryotes from protozoan to human. The small G protein superfamily includes Ras, Rho Rab, Rac, Sar1/Arf and Ran homologs, which take part in numerous and diverse cellular processes, such as gene expression, cytoskeleton reorganization, microtubule organization, and vesicular and nuclear transport. These proteins share a common structural core, described as the G domain, and significant sequence similarity. In this paper we review the available data on G domain structure, together with a detailed analysis of the mechanism of action. We also present small G protein regulators: GTPase activating proteins that bind to a catalytic G domain and increase its low intrinsic hydrolase activity, GTPase dissociation inhibitors that stabilize the GDP-bound, inactive state of G proteins, and guanine nucleotide exchange factors that accelerate nucleotide exchange in response to cellular signals. Additionally, in this paper we describe some aspects of small G protein interactions with downstream effectors.

Ograniczanie wyników

Involvement of Rac-Cdc42-PAK pathway in cytoskeletal rearrangements

Dynamin - A mechanoenzyme scissing membrane vesicles

The identification and characterization of a new GTP-binding protein [Gbp45] involved in cell proliferation and death related to mitochondrial function

The membrane-cytoskeleton interface controls platelet shape change

Transport functions and physiological significance of 76 kDa Ral-binding GTPase activating protein [RLIP76]

Rho kinase in the regulation of cell death and survival

The GTPase domain of Galphao contributes to the functional interactions of Galphao with the promyelocytic leukemia zinc finger protein

Structure of small G proteins and their regulators