scholarly journals Characterization of cytoskeletal protein 4.1R interaction with NHE1 (Na+/H+ exchanger isoform 1)

2012 ◽  
Vol 446 (3) ◽  
pp. 427-435 ◽  
Author(s):  
Wataru Nunomura ◽  
Sheryl P. Denker ◽  
Diane L. Barber ◽  
Yuichi Takakuwa ◽  
Philippe Gascard
Keyword(s):  
Amino Acids ◽  
Protein Interaction ◽  
Cytoskeletal Protein ◽  
Functional Interaction ◽  
Ferm Domain ◽  
Protein Protein Interaction ◽  
Nhe1 Activity ◽  
Acidic Conditions ◽  
Protein 4.1R

NHE1 (Na+/H+ exchanger isoform 1) has been reported to be hyperactive in 4.1R-null erythrocytes [Rivera, De Franceschi, Peters, Gascard, Mohandas and Brugnara (2006) Am. J. Physiol. Cell Physiol. 291, C880–C886], supporting a functional interaction between NHE1 and 4.1R. In the present paper we demonstrate that 4.1R binds directly to the NHE1cd (cytoplasmic domain of NHE1) through the interaction of an EED motif in the 4.1R FERM (4.1/ezrin/radixin/moesin) domain with two clusters of basic amino acids in the NHE1cd, K519R and R556FNKKYVKK, previously shown to mediate PIP2 (phosphatidylinositol 4,5-bisphosphate) binding [Aharonovitz, Zaun, Balla, York, Orlowski and Grinstein (2000) J. Cell. Biol. 150, 213–224]. The affinity of this interaction (Kd=100–200 nM) is reduced in hypertonic and acidic conditions, demonstrating that this interaction is of an electrostatic nature. The binding affinity is also reduced upon binding of Ca2+/CaM (Ca2+-saturated calmodulin) to the 4.1R FERM domain. We propose that 4.1R regulates NHE1 activity through a direct protein–protein interaction that can be modulated by intracellular pH and Na+ and Ca2+ concentrations.

scholarly journals Protein-protein interaction analysis for functional characterization of helicases

Methods ◽  
2016 ◽  
Vol 108 ◽  
pp. 56-64 ◽  
Author(s):  
Boris L. Zybailov ◽  
Alicia K. Byrd ◽  
Galina V. Glazko ◽  
Yasir Rahmatallah ◽  
Kevin D. Raney
Keyword(s):  
Protein Interaction ◽  
Interaction Analysis ◽  
Functional Characterization ◽  
Protein Protein Interaction

scholarly journals Characterization of Protein-Protein Interaction Interfaces from a Single Species

PLoS ONE ◽  
2011 ◽  
Vol 6 (6) ◽  
pp. e21053 ◽  
Author(s):  
David Talavera ◽  
David L. Robertson ◽  
Simon C. Lovell
Keyword(s):  
Protein Interaction ◽  
Single Species ◽  
Protein Protein Interaction

scholarly journals RBP-L, a transcription factor related to RBP-Jkappa.

1997 ◽  
Vol 17 (5) ◽  
pp. 2679-2687 ◽  
Author(s):  
S Minoguchi ◽  
Y Taniguchi ◽  
H Kato ◽  
T Okazaki ◽  
L J Strobl ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Notch Receptor ◽  
In Vitro Assays ◽  
Functional Interaction ◽  
Protein Protein Interaction ◽  
Isolation And Characterization ◽  
Signalling Molecule

RBP-Jkappa is a sequence-specific DNA binding protein which plays a central role in signalling downstream of the Notch receptor by physically interacting with its intracellular region. Although at least four Notch genes exist in mammals, it is unknown whether each Notch requires a specific downstream signalling molecule. Here we report isolation and characterization of a mouse RBP-Jkappa-related gene named RBP-L that is expressed almost exclusively in lung, in contrast to the ubiquitous expression of RBP-Jkappa. For simplicity, we propose to call RBP-Jkappa RBP-J. The RBP-L protein bound to a DNA sequence almost identical to that of RBP-J. Surprisingly, RBP-L did not interact with any of the known four mouse Notch proteins. Although we found that RBP-L and EBNA-2 cooperated in transcriptional activation, they did not show significantly strong protein-protein interaction that can be detected by several in vivo and in vitro assays. This is again in contrast to physical association of RBP-J with EBNA-2. Several models to explain functional interaction between RBP-L and EBNA-2 are discussed.

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