Based on the excellent High-Affi™ technology, Creative Biolabs has the capable of providing high affinity site-specific anti-phosphocholinated antibody production services. These antibodies are produced by optimized immunization or phage display technology. The antibody specifically reacts with phosphocholinated peptides but does not cross-react with unmodified peptides or other modifications.
The characteristics of phosphocholination
Phosphocholination is a recent found important post-translational modification used by intracellular pathogenic bacteria during the infection process. After infection, the pathogen injects numerous effector proteins into the host cell to establish a vacuole for proliferation.
The effector protein AnkX transfers a phosphocholine group to serine or threonine residues of Rab1b and Rab35 using CDP-choline as a donor. Observation has shown that AnkX can catalyze autophosphocholination. The transferase activity of AnkX protein requires a conserved histidine (H229) residue located in the FIC domain. Like AMPylation, phosphocholination is also a reversible and dynamic modification, which can be taken off by dephosphocholinase Lem3.
Studies have shown that AnkX is specificity for Rab1 family members. Phosphocholination of Rab GTPases also represents a mechanism by which bacterial proteins can alter host cell functions. The results of mass spectrometry show that serine 79 of Rab1 is the specific site modified by AnkX. Site mutation revealed that Rab1S79A interfered with the secretion of alkaline phosphatase. Therefore, AnkX is targeting a residue in Rab1 that is critical for function.
Rab35 participates in the traffic of recycling endosomes toward the plasma membrane. There was a significant increase in the number of cells containing enlarged early endosomes in cells producing AnkX compared to cells producing AnkXH229A, consistent with the function of Rab35 being perturbed by phosphocholination.
Fig.1 The dynamic process of phosphocholination. (Heller K, et al. 2015)
The function of phosphocholination on Rab1 or Rab35
Phosphocholination of Rab proteins has involved a large number of interactions with different classes of protein factors, including GEFs, Rab effectors GAPs, Rab escort protein and GDP dissociation inhibitor.
Antibody is the most useful tool in identifying the unknown substrates of post-translational modifications, especially for the newly discovered types. Creative Biolabs is a global leader in antibody discovery and production of post-translational modification. Based on the High-Affi™ technology, our company can supply the best quality products to customers. In addition, you can customize the most ideal antibodies from us according to your projects.
Creative Biolabs can provide a comprehensive list of PTM-specific antibody production services of your choice.