Transduction of full-length TAT fusion proteins into mammalian cells: TAT-p27Kip1 induces cell migration

10.1038/4042 ◽  
1998 ◽  
Vol 4 (12) ◽  
pp. 1449-1452 ◽  
Author(s):  
Hikaru Nagahara ◽  
Adamina M. Vocero-Akbani ◽  
Eric L. Snyder ◽  
Alan Ho ◽  
Dawn G. Latham ◽  
...  
2010 ◽  
Vol 21 (18) ◽  
pp. 3162-3170 ◽  
Author(s):  
Chang-Hoon Choi ◽  
Hitesh Patel ◽  
Diane L. Barber

Increased intracellular pH is an evolutionarily conserved signal necessary for directed cell migration. We reported previously that in Dictyostelium cells lacking H+ efflux by a Na+-H+ exchanger (NHE; Ddnhe1−), chemotaxis is impaired and the assembly of filamentous actin (F-actin) is attenuated. We now describe a modifier screen that reveals the C-terminal fragment of actin-interacting protein 1 (Aip1) enhances the chemotaxis defect of Ddnhe1− cells but has no effect in wild-type Ax2 cells. However, expression of full-length Aip1 mostly suppresses chemotaxis defects of Ddnhe1− cells and restores F-actin assembly. Aip1 functions to promote cofilin-dependent actin remodeling, and we found that although full-length Aip1 binds cofilin and F-actin, the C-terminal fragment binds cofilin but not F-actin. Because pH-dependent cofilin activity is attenuated in mammalian cells lacking H+ efflux by NHE1, our current data suggest that full-length Aip1 facilitates F-actin assembly when cofilin activity is limited. We predict the C-terminus of Aip1 enhances defective chemotaxis of Ddnhe1− cells by sequestering the limited amount of active cofilin without promoting F-actin assembly. Our findings indicate a cooperative role of Aip1 and cofilin in pH-dependent cell migration, and they suggest defective chemotaxis in Ddnhe1− cells is determined primarily by loss of cofilin-dependent actin dynamics.


2019 ◽  
Vol 19 (25) ◽  
pp. 2271-2282 ◽  
Author(s):  
Bo Lu ◽  
Xue-Hui Liu ◽  
Si-Ming Liao ◽  
Zhi-Long Lu ◽  
Dong Chen ◽  
...  

Polysialic acid (polySia) is a novel glycan that posttranslationally modifies neural cell adhesion molecules (NCAMs) in mammalian cells. Up-regulation of polySia-NCAM expression or NCAM polysialylation is associated with tumor cell migration and progression in many metastatic cancers and neurocognition. It has been known that two highly homologous mammalian polysialyltransferases (polySTs), ST8Sia II (STX) and ST8Sia IV (PST), can catalyze polysialylation of NCAM, and two polybasic domains, polybasic region (PBR) and polysialyltransferase domain (PSTD) in polySTs play key roles in affecting polyST activity or NCAM polysialylation. However, the molecular mechanisms of NCAM polysialylation and cell migration are still not entirely clear. In this minireview, the recent research results about the intermolecular interactions between the PBR and NCAM, the PSTD and cytidine monophosphate-sialic acid (CMP-Sia), the PSTD and polySia, and as well as the intramolecular interaction between the PBR and the PSTD within the polyST, are summarized. Based on these cooperative interactions, we have built a novel model of NCAM polysialylation and cell migration mechanisms, which may be helpful to design and develop new polysialyltransferase inhibitors.


Circulation ◽  
1998 ◽  
Vol 98 (24) ◽  
pp. 2744-2752 ◽  
Author(s):  
Kristian Riesbeck ◽  
Daxin Chen ◽  
Geoffrey Kemball-Cook ◽  
John H. McVey ◽  
Andrew J. T. George ◽  
...  

2021 ◽  
Vol 2021 (8) ◽  
pp. pdb.prot100040
Author(s):  
Edward A. Greenfield ◽  
James DeCaprio ◽  
Mohan Brahmandam

2010 ◽  
Vol 78 (5) ◽  
pp. 2079-2088 ◽  
Author(s):  
Christopher T. D. Price ◽  
Souhaila Al-Khodor ◽  
Tasneem Al-Quadan ◽  
Yousef Abu Kwaik

ABSTRACT The Dot/Icm-translocated ankyrin B (AnkB) effector of Legionella pneumophila exhibits molecular mimicry of eukaryotic F-box proteins and is essential for intracellular replication in macrophages and protozoa. In addition to two eukaryotic-like ankyrin (ANK) domains, AnkB harbors a conserved eukaryotic F-box domain, which is involved in polyubiquitination of proteins throughout the eukaryotic kingdom. We have recently shown that the F-box domain of the AnkB effector is essential for decoration of the Legionella-containing vacuole (LCV) with polyubiquitinated proteins within macrophages and protozoan hosts. To decipher the role of the two ANK domains in the function of AnkB, we have constructed in-frame deletion of either or both of the ANK domain-encoding regions (ankBΔA1, ankBΔA2, and ankBΔA1A2) to trans-complement the ankB null mutant. Deletion of the ANK domains results in defects in intracellular proliferation and decoration of the LCV with polyubiquitinated proteins. Export of the truncated variants of AnkB was reduced, and this may account for the observed defects. However, while full-length AnkB ectopically expressed in mammalian cells trans-rescues the ankB null mutant for intracellular proliferation, ectopic expression of AnkBΔA1, AnkBΔA2, and AnkBΔA1A2 fails to trans-rescue the ankB null mutant. Importantly, ectopically expressed full-length AnkB is targeted to the host cell plasma membrane, where it recruits polyubiquitinated proteins. In contrast, AnkBΔA1, AnkBΔA2, and AnkBΔA1A2 are diffusely distributed throughout the cytosol and fail to recruit polyubiquitinated proteins. We conclude that the two eukaryotic-like ANK domains of AnkB are essential for intracellular proliferation, for targeting AnkB to the host membranes, and for decoration of the LCV with polyubiquitinated proteins.


1994 ◽  
Vol 14 (3) ◽  
pp. 1721-1732 ◽  
Author(s):  
C A Bunker ◽  
R E Kingston

The Polycomb group (Pc-G) genes are essential for maintaining the proper spatially restricted expression pattern of the homeotic loci during Drosophila development. The Pc-G proteins appear to function at target loci to maintain a state of transcriptional repression. The murine oncogene bmi-1 has significant homology to the Pc-G gene Posterior sex combs (Psc) and a highly related gene, Suppressor two of zeste [Su(z)2]. We show here that the proteins encoded by bmi-1 and the Pc-G genes Polycomb (Pc) and Psc as well as Su(z)2 mediate repression in mammalian cells when targeted to a promoter by LexA in a cotransfection system. These fusion proteins repress activator function by as much as 30-fold, and the effect on different activation domains is distinct for each Pc-G protein. Repression is observed when the LexA fusion proteins are bound directly adjacent to activator binding sites and also when bound 1,700 bases from the promoter. These data demonstrate that the products of the Pc-G genes can significantly repress activator function on transiently introduced DNA. We suggest that this function contributes to the stable repression of targeted loci during development.


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