scholarly journals Novel Binding Partners for CCT and PhLP1 Suggest a Common Folding Mechanism for WD40 Proteins with a 7-Bladed Beta-Propeller Structure

Proteomes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 40
Author(s):  
Wai Shun Mak ◽  
Tsz Ming Tsang ◽  
Tsz Yin Chan ◽  
Georgi L. Lukov
Keyword(s):  
G Protein ◽  
Protein Family ◽  
Β Subunit ◽  
Binding Partner ◽  
Folding Mechanism ◽  
Binding Partners

This study investigates whether selected WD40 proteins with a 7-bladed β-propeller structure, similar to that of the β subunit of the G protein heterotrimer, interact with the cytosolic chaperonin CCT and its known binding partner, PhLP1. Previous studies have shown that CCT is required for the folding of the Gβ subunit and other WD40 proteins. The role of PhLP1 in the folding of Gβ has also been established, but it is unknown if PhLP1 assists in the folding of other Gβ-like proteins. The binding of three Gβ-like proteins, TBL2, MLST8 and CDC20, to CCT and PhLP1, was demonstrated in this study. Co-immunoprecipitation assays identified one novel binding partner for CCT and three new interactors for PhLP1. All three of the studied proteins interact with CCT and PhLP1, suggesting that these proteins may have a folding machinery in common with that of Gβ and that the well-established Gβ folding mechanism may have significantly broader biological implications than previously thought. These findings contribute to continuous efforts to determine common traits and unique differences in the folding mechanism of the WD40 β-propeller protein family, and the role PhLP1 has in this process.

scholarly journals Distribution of Activator of G-Protein Signaling 3 within the Aggresomal Pathway: Role of Specific Residues in the Tetratricopeptide Repeat Domain and Differential Regulation by the AGS3 Binding Partners Giα and Mammalian Inscuteable

2010 ◽  
Vol 30 (6) ◽  
pp. 1528-1540 ◽  
Author(s):  
Ali Vural ◽  
Sadik Oner ◽  
Ningfei An ◽  
Violaine Simon ◽  
Dzwokai Ma ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Single Nucleotide ◽  
Signaling Systems ◽  
Binding Partners ◽  
Repeat Domain ◽  
Tetratricopeptide Repeat Domain ◽  
Tpr Domain

ABSTRACT AGS3, a receptor-independent activator of G-protein signaling, is involved in unexpected functional diversity for G-protein signaling systems. AGS3 has seven tetratricopeptide (TPR) motifs upstream of four G-protein regulatory (GPR) motifs that serve as docking sites for Giα-GDP. The positioning of AGS3 within the cell and the intramolecular dynamics between different domains of the proteins are likely key determinants of their ability to influence G-protein signaling. We report that AGS3 enters into the aggresome pathway and that distribution of the protein is regulated by the AGS3 binding partners Giα and mammalian Inscuteable (mInsc). Giα rescues AGS3 from the aggresome, whereas mInsc augments the aggresome-like distribution of AGS3. The distribution of AGS3 to the aggresome is dependent upon the TPR domain, and it is accelerated by disruption of the TPR organizational structure or introduction of a nonsynonymous single-nucleotide polymorphism. These data present AGS3, G-proteins, and mInsc as candidate proteins involved in regulating cellular stress associated with protein-processing pathologies.

scholarly journals A Phytophthora infestans G-Protein β Subunit Is Involved in Sporangium Formation

2003 ◽  
Vol 2 (5) ◽  
pp. 971-977 ◽  
Author(s):  
Maita Latijnhouwers ◽  
Francine Govers
Keyword(s):  
Phytophthora Infestans ◽  
G Protein ◽  
Aerial Mycelium ◽  
Β Subunit ◽  
Α Subunit ◽  
Extracellular Signals ◽  
Intermediate Phenotypes ◽  
Wide Range ◽  
Sucrose Medium

ABSTRACT The heterotrimeric G-protein pathway regulates cellular responses to a wide range of extracellular signals in virtually all eukaryotes. It also controls various developmental processes in the oomycete plant pathogen Phytophthora infestans, as was concluded from previous studies on the role of the G-protein α-subunit PiGPA1 in this organism. The expression of the P. infestans G-protein β-subunit gene Pigpb1 was induced in nutrient-starved mycelium before the onset of sporangium formation. The gene was hardly expressed in mycelium incubated in rich growth medium. The introduction of additional copies of Pigpb1 into the genome led to silencing of the gene and resulted in transformants deficient in PiGPB1. These Pigpb1-silenced mutants formed very few asexual spores (sporangia) when cultured in rye sucrose medium and produced a denser mat of aerial mycelium than the wild type. Partially Pigpb1-silenced mutants showed intermediate phenotypes with regard to sporulation, and a relatively large number of their sporangia were malformed. The results show that PiGPB1 is important for vegetative growth and sporulation and, therefore, for the pathogenicity of this organism.

Cloning and Analyzing of G-protein β-Subunit Gene in Rhizoctonia solani Causing Soybean Sharp Eyespot

2009 ◽  
Vol 35 (2) ◽  
pp. 370-374
Author(s):  
Bing-Tian MA ◽  
Guang-Lin QU ◽  
Wen-Juan HUANG ◽  
Yu-Fan LIN ◽  
Shi-Gui LI
Keyword(s):  
Rhizoctonia Solani ◽  
G Protein ◽  
Β Subunit ◽  
Subunit Gene ◽  
Sharp Eyespot

scholarly journals Optineurin links myosin VI to the Golgi complex and is involved in Golgi organization and exocytosis

2005 ◽  
Vol 169 (2) ◽  
pp. 285-295 ◽  
Author(s):  
Daniela A. Sahlender ◽  
Rhys C. Roberts ◽  
Susan D. Arden ◽  
Giulietta Spudich ◽  
Marcus J. Taylor ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Rna Interference ◽  
Vesicular Stomatitis Virus ◽  
Protein Interaction ◽  
Golgi Complex ◽  
Myosin Vi ◽  
Binding Partner ◽  
Binding Partners ◽  
Vesicular Stomatitis ◽  
Golgi Organization

Myosin VI plays a role in the maintenance of Golgi morphology and in exocytosis. In a yeast 2-hybrid screen we identified optineurin as a binding partner for myosin VI at the Golgi complex and confirmed this interaction in a range of protein interaction studies. Both proteins colocalize at the Golgi complex and in vesicles at the plasma membrane. When optineurin is depleted from cells using RNA interference, myosin VI is lost from the Golgi complex, the Golgi is fragmented and exocytosis of vesicular stomatitis virus G-protein to the plasma membrane is dramatically reduced. Two further binding partners for optineurin have been identified: huntingtin and Rab8. We show that myosin VI and Rab8 colocalize around the Golgi complex and in vesicles at the plasma membrane and overexpression of constitutively active Rab8-Q67L recruits myosin VI onto Rab8-positive structures. These results show that optineurin links myosin VI to the Golgi complex and plays a central role in Golgi ribbon formation and exocytosis.

scholarly journals Shared Components of the FRQ-Less Oscillator and TOR Pathway Maintain Rhythmicity in Neurospora

2021 ◽  
pp. 074873042199994
Author(s):  
Rosa Eskandari ◽  
Lalanthi Ratnayake ◽  
Patricia L. Lakin-Thomas
Keyword(s):  
Circadian Rhythms ◽  
Clock Genes ◽  
Nutrient Sensing ◽  
Mass Spectrometry Analysis ◽  
Growth Responses ◽  
Tor Pathway ◽  
Spectrometry Analysis ◽  
Binding Partner ◽  
Binding Partners ◽  
Free Running

Molecular models for the endogenous oscillators that drive circadian rhythms in eukaryotes center on rhythmic transcription/translation of a small number of “clock genes.” Although substantial evidence supports the concept that negative and positive transcription/translation feedback loops (TTFLs) are responsible for regulating the expression of these clock genes, certain rhythms in the filamentous fungus Neurospora crassa continue even when clock genes ( frq, wc-1, and wc-2) are not rhythmically expressed. Identification of the rhythmic processes operating outside of the TTFL has been a major unresolved area in circadian biology. Our lab previously identified a mutation ( vta) that abolishes FRQ-less rhythmicity of the conidiation rhythm and also affects rhythmicity when FRQ is functional. Further studies identified the vta gene product as a component of the TOR (Target of Rapamycin) nutrient-sensing pathway that is conserved in eukaryotes. We now report the discovery of TOR pathway components including GTR2 (homologous to the yeast protein Gtr2, and RAG C/D in mammals) as binding partners of VTA through co-immunoprecipitation (IP) and mass spectrometry analysis using a VTA-FLAG strain. Reciprocal IP with GTR2-FLAG found VTA as a binding partner. A Δ gtr2 strain was deficient in growth responses to amino acids. Free-running conidiation rhythms in a FRQ-less strain were abolished in Δ gtr2. Entrainment of a FRQ-less strain to cycles of heat pulses demonstrated that Δ gtr2 is defective in entrainment. In all of these assays, Δ gtr2 is similar to Δ vta. In addition, expression of GTR2 protein was found to be rhythmic across two circadian cycles, and functional VTA was required for GTR2 rhythmicity. FRQ protein exhibited the expected rhythm in the presence of GTR2 but the rhythmic level of FRQ dampened in the absence of GTR2. These results establish association of VTA with GTR2, and their role in maintaining functional circadian rhythms through the TOR pathway.

scholarly journals Role of G protein beta gamma subunits in the regulation of the plasma membrane Ca2+ pump.

1992 ◽  
Vol 267 (4) ◽  
pp. 2375-2379 ◽  
Author(s):  
S Lotersztajn ◽  
C Pavoine ◽  
P Deterre ◽  
J Capeau ◽  
A Mallat ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
G Protein ◽  
Gamma Subunits
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