scholarly journals The Yersinia pestis YscY Protein Directly Binds YscX, a Secreted Component of the Type III Secretion Machinery

2000 ◽  
Vol 182 (7) ◽  
pp. 1834-1843 ◽  
Author(s):  
James B. Day ◽  
Gregory V. Plano
Keyword(s):  
Yersinia Pestis ◽  
Type Iii Secretion ◽  
Coiled Coil ◽  
Eukaryotic Cell ◽  
Pellet Fraction ◽  
Virulence Proteins ◽  
Coiled Coil Region ◽  
Cell Pellet ◽  
V Antigen ◽  
Sequence Similarities

ABSTRACT Human pathogenic yersiniae organisms export and translocate the Yop virulence proteins and V antigen upon contact with a eukaryotic cell.Yersinia pestis mutants defective for production of YscX or YscY were unable to export the Yops and V antigen. YscX and YscY were both present in the Y. pestis cell pellet fraction; however, YscX was also found in the culture supernatant. YscY showed structural and amino acid sequence similarities to the Syc family of proteins. YscY specifically recognized and bound to a region of YscX that included a predicted coiled-coil region. These data suggest that YscY may function as a chaperone for YscX in Y. pestis.

scholarly journals Yersinia pestis YscG Protein Is a Syc-Like Chaperone That Directly Binds YscE

2000 ◽  
Vol 68 (11) ◽  
pp. 6466-6471 ◽  
Author(s):  
James B. Day ◽  
Inna Guller ◽  
Gregory V. Plano
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Yersinia Pestis ◽  
Eukaryotic Cell ◽  
Virulence Proteins ◽  
Sequence Similarities

ABSTRACT Pathogenic Yersinia species secrete virulence proteins, termed Yersinia outer proteins (Yops), upon contact with a eukaryotic cell. The secretion machinery is composed of 21Yersinia secretion (Ysc) proteins. Yersinia pestis mutants defective in expression of YscG or YscE were unable to export the Yops. YscG showed structural and limited amino-acid-sequence similarities to members of the specific Yop chaperone (Syc) family of proteins. YscG specifically recognized and bound YscE; however, unlike previously characterized Syc substrates, YscE was not exported from the cell. These data suggest that YscG functions as a chaperone for YscE.

scholarly journals YopD of Yersinia pestis Plays a Role in Negative Regulation of the Low-Calcium Response in Addition to Its Role in Translocation of Yops

1998 ◽  
Vol 180 (2) ◽  
pp. 350-358 ◽  
Author(s):  
Andrew W. Williams ◽  
Susan C. Straley
Keyword(s):  
Yersinia Pestis ◽  
Type Iii Secretion ◽  
Negative Regulation ◽  
Negative Regulator ◽  
Cell Contact ◽  
Virulence Proteins ◽  
The Stability ◽  
Rate Limiting ◽  
In Vitro Induction

ABSTRACT Yersinia pestis produces a set of virulence proteins (Yops and LcrV) that are expressed at high levels and secreted by a type III secretion system (Ysc) upon bacterium-host cell contact, and four of the Yops are vectorially translocated into eukaryotic cells. YopD, YopB, and YopK are required for the translocation process. In vitro, induction and secretion occur at 37°C in the absence of calcium. LcrH (also called SycD), a protein required for the stability and secretion of YopD, had initially been identified as a negative regulator of Yop expression. In this study, we constructed ayopD mutation in both wild-type and secretion-defective (ysc) Y. pestis to determine if thelcrH phenotype could be attributed to the decreased stability of YopD. These mutants were constitutively induced for expression of Yops and LcrV, despite the presence of the secreted negative regulator LcrQ, demonstrating that YopD is involved in negative regulation, regardless of a functioning Ysc system. Normally, secretion of Yops and LcrV is blocked in the presence of calcium. The single yopD mutant was not completely effective in blocking secretion: LcrV was secreted equally well in the presence and absence of calcium, while there was partial secretion of Yops in the presence of calcium. YopD is probably not rate limiting for negative regulation, as increasing levels of YopD did not result in decreased Yop expression. Overexpression of LcrQ in the yopD mutant had no significant effect on Yop expression, whereas increased levels of LcrQ in the parent resulted in decreased levels of Yops. These results indicate that LcrQ requires YopD to function as a negative regulator.

The SPI2-encoded SseA chaperone has discrete domains required for SseB stabilization and export, and binds within the C-terminus of SseB and SseD

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2055-2068 ◽  
Author(s):  
Daniel V. Zurawski ◽  
Murry A. Stein
Keyword(s):  
Type Iii Secretion ◽  
Coiled Coil ◽  
Amphipathic Helix ◽  
Yeast Two Hybrid ◽  
C Terminus ◽  
N Terminus ◽  
Domain Mapping ◽  
Self Association ◽  
Discrete Domains ◽  
Two Hybrid

SseA, a key Salmonella virulence determinant, is a small, basic pI protein encoded within the Salmonella pathogenicity island 2 and serves as a type III secretion system chaperone for SseB and SseD. Both SseA partners are subunits of the surface-localized translocon module that delivers effectors into the host cell; SseB is predicted to compose the translocon sheath and SseD is a putative translocon pore subunit. In this study, SseA molecular interactions with its partners were characterized further. Yeast two-hybrid screens indicate that SseA binding requires a C-terminal domain within both partners. An additional central domain within SseD was found to influence binding. The SseA-binding region within SseB was found to encompass a predicted amphipathic helix of a type participating in coiled-coil interactions that are implicated in the assembly of translocon sheaths. Deletions that impinge upon this putative coiled-coiled domain prevent SseA binding, suggesting that SseA occupies a portion of the coiled-coil. SseA occupancy of this motif is envisioned to be sufficient to prevent premature SseB self-association inside bacteria. Domain mapping on the chaperone was also performed. A deletion of the SseA N-terminus, or site-directed mutations within this region, allowed stabilization of SseB, but its export was disrupted. Therefore, the N-terminus of SseA provides a function that is essential for SseB export, but dispensable for partner binding and stabilization.

scholarly journals A Coiled-Coil Domain of Melanophilin Is Essential for Myosin Va Recruitment and Melanosome Transport in Melanocytes

2006 ◽  
Vol 17 (11) ◽  
pp. 4720-4735 ◽  
Author(s):  
Alistair N. Hume ◽  
Abul K. Tarafder ◽  
José S. Ramalho ◽  
Elena V. Sviderskaya ◽  
Miguel C. Seabra
Keyword(s):  
Coiled Coil ◽  
Binding Domain ◽  
Actin Binding ◽  
Binding Studies ◽  
Null Cell ◽  
Coiled Coil Region ◽  
Actin Binding Domain ◽  
Transport Assay ◽  
Myosin Va

Melanophilin (Mlph) regulates retention of melanosomes at the peripheral actin cytoskeleton of melanocytes, a process essential for normal mammalian pigmentation. Mlph is proposed to be a modular protein binding the melanosome-associated protein Rab27a, Myosin Va (MyoVa), actin, and microtubule end-binding protein (EB1), via distinct N-terminal Rab27a-binding domain (R27BD), medial MyoVa-binding domain (MBD), and C-terminal actin-binding domain (ABD), respectively. We developed a novel melanosome transport assay using a Mlph-null cell line to study formation of the active Rab27a:Mlph:MyoVa complex. Recruitment of MyoVa to melanosomes correlated with rescue of melanosome transport and required intact R27BD together with MBD exon F–binding region (EFBD) and unexpectedly a potential coiled-coil forming sequence within ABD. In vitro binding studies indicate that the coiled-coil region enhances binding of MyoVa by Mlph MBD. Other regions of Mlph reported to interact with MyoVa globular tail, actin, or EB1 are not essential for melanosome transport rescue. The strict correlation between melanosomal MyoVa recruitment and rescue of melanosome distribution suggests that stable interaction with Mlph and MyoVa activation are nondissociable events. Our results highlight the importance of the coiled-coil region together with R27BD and EFBD regions of Mlph in the formation of the active melanosomal Rab27a-Mlph-MyoVa complex.

scholarly journals Tandem Translation Generates a Chaperone for the Salmonella Type III Secretion System Protein SsaQ

2011 ◽  
Vol 286 (41) ◽  
pp. 36098-36107 ◽  
Author(s):  
Xiu-Jun Yu ◽  
Mei Liu ◽  
Steve Matthews ◽  
David W. Holden
Keyword(s):  
Type Iii Secretion ◽  
Ex Vivo ◽  
Eukaryotic Cell ◽  
Effector Proteins ◽  
Secretion Systems ◽  
Type Iii ◽  
Type Iii Secretion Systems ◽  
Function Loss ◽  
Bacterial Cytoplasm

Type III secretion systems (T3SSs) of bacterial pathogens involve the assembly of a surface-localized needle complex, through which translocon proteins are secreted to form a pore in the eukaryotic cell membrane. This enables the transfer of effector proteins from the bacterial cytoplasm to the host cell. A structure known as the C-ring is thought to have a crucial role in secretion by acting as a cytoplasmic sorting platform at the base of the T3SS. Here, we studied SsaQ, an FliN-like putative C-ring protein of the Salmonella pathogenicity island 2 (SPI-2)-encoded T3SS. ssaQ produces two proteins by tandem translation: a long form (SsaQL) composed of 322 amino acids and a shorter protein (SsaQS) comprising the C-terminal 106 residues of SsaQL. SsaQL is essential for SPI-2 T3SS function. Loss of SsaQS impairs the function of the T3SS both ex vivo and in vivo. SsaQS binds to its corresponding region within SsaQL and stabilizes the larger protein. Therefore, SsaQL function is optimized by a novel chaperone-like protein, produced by tandem translation from its own mRNA species.

scholarly journals Over-Production, Crystallization, and Preliminary X-ray Crystallographic Analysis of a Coiled-Coil Region in Human Pericentrin

Crystals ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. 296
Author(s):  
Min Kim ◽  
Jeong Park ◽  
Yeowon Sim ◽  
Doheum Kim ◽  
Jeong Sim ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Crystallographic Analysis ◽  
X Ray ◽  
Coiled Coil Region

Identification of Proteins That Interact with the Central Coiled-Coil Region of the Human Protein Kinase NEK1†

Biochemistry ◽  
2003 ◽  
Vol 42 (51) ◽  
pp. 15369-15376 ◽  
Author(s):  
Marcelo J. Surpili ◽  
Tatiana M. Delben ◽  
Jörg Kobarg
Keyword(s):  
Protein Kinase ◽  
Coiled Coil ◽  
Human Protein ◽  
Human Protein Kinase ◽  
Coiled Coil Region
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