A twist in the ABC: regulation of ABC transporter trafficking and transport by FK506‐binding proteins

A recombinant macrophage infectivity potentiator (rMIP) protein ofNeisseria meningitidisinduces significant serum bactericidal antibody production in mice and is a candidate meningococcal vaccine antigen. However, bioinformatics analysis of MIP showed some amino acid sequence similarity to human FK506-binding proteins (FKBPs) in residues 166 to 252 located in the globular domain of the protein. To circumvent the potential concern over generating antibodies that could recognize human proteins, we immunized mice with recombinant truncated type I rMIP proteins that lacked the globular domain and the signal leader peptide (LP) signal sequence (amino acids 1 to 22) and contained the His purification tag at either the N or C terminus (C-term). The immunogenicity of truncated rMIP proteins was compared to that of full (i.e., full-length) rMIP proteins (containing the globular domain) with either an N- or C-terminal His tag and with or without the LP sequence. By comparing the functional murine antibody responses to these various constructs, we determined that C-term His truncated rMIP (−LP) delivered in liposomes induced high levels of antibodies that bound to the surface of wild-type but not Δmipmutant meningococci and showed bactericidal activity against homologous type I MIP (median titers of 128 to 256) and heterologous type II and III (median titers of 256 to 512) strains, thereby providing at least 82% serogroup B strain coverage. In contrast, in constructs lacking the LP, placement of the His tag at the N terminus appeared to abrogate bactericidal activity. The strategy used in this study would obviate any potential concerns regarding the use of MIP antigens for inclusion in bacterial vaccines.

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Utilization of an Intracellular Calcium Mobilization Assay for the Screening of Transduced FK506-Binding Proteins

Assay and Drug Development Technologies ◽

10.1089/adt.2021.065 ◽

2021 ◽

Author(s):

Hyun Ju Cha ◽

Hyunjin Lee ◽

Eun Ji Yeo ◽

Hyeon Ji Yeo ◽

Yeon Joo Choi ◽

...

Keyword(s):

Intracellular Calcium ◽

Binding Proteins ◽

Calcium Mobilization ◽

Intracellular Calcium Mobilization ◽

Fk506 Binding Proteins ◽

Calcium Mobilization Assay

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The Adc/Lmb System Mediates Zinc Acquisition in Streptococcus agalactiae and Contributes to Bacterial Growth and Survival

Journal of Bacteriology ◽

10.1128/jb.00614-16 ◽

2016 ◽

Vol 198 (24) ◽

pp. 3265-3277 ◽

Cited By ~ 17

Author(s):

Pauline Moulin ◽

Kévin Patron ◽

Camille Cano ◽

Mohamed Amine Zorgani ◽

Emilie Camiade ◽

...

Keyword(s):

Abc Transporter ◽

Bacterial Growth ◽

Streptococcus Agalactiae ◽

Binding Proteins ◽

Biological Fluids ◽

Infection Process ◽

Content Type ◽

Growth And Survival ◽

Vital Functions ◽

Bacterial Growth And Survival

ABSTRACT The Lmb protein of Streptococcus agalactiae is described as an adhesin that binds laminin, a component of the human extracellular matrix. In this study, we revealed a new role for this protein in zinc uptake. We also identified two Lmb homologs, AdcA and AdcAII, redundant binding proteins that combine with the AdcCB translocon to form a zinc-ABC transporter. Expression of this transporter is controlled by the zinc concentration in the medium through the zinc-dependent regulator AdcR. Triple deletion of lmb , adcA , and adcAII , or that of the adcCB genes, impaired growth and cell separation in a zinc-restricted environment. Moreover, we found that this Adc zinc-ABC transporter promotes S. agalactiae growth and survival in some human biological fluids, suggesting that it contributes to the infection process. These results indicated that zinc has biologically vital functions in S. agalactiae and that, under the conditions tested, the Adc/Lmb transporter constitutes the main zinc acquisition system of the bacterium. IMPORTANCE A zinc transporter, composed of three redundant binding proteins (Lmb, AdcA, and AdcAII), was characterized in Streptococcus agalactiae . This system was shown to be essential for bacterial growth and morphology in zinc-restricted environments, including human biological fluids.

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