Anti-CD2BP2 polyclonal antibody

Protein-protein interactions are often mediated by small domains that recognize solvent-exposed peptide sequences. Deciphering the recognition code for these adapter domains is an important step in the understanding of multi-protein assemblies. Here, we investigate the sequence requirements for the CD2BP2-GYF domain, a proline-rich sequence binding module previously shown to be involved in T cell signaling. We show that the signature (R/K/G)XXPPGX(R/K) defines a preferred peptide-binding motif that is present in several proteins of the splicing machinery. Specifically, the core small nuclear ribonucleoprotein, SmB/B', contains several PPP-PGMR motifs that interact with the CD2BP2-GYF domain in vitro and in vivo. The colocalization of CD2BP2 and SmB proteins in the nucleus of Jurkat T cells and HeLa cells suggests a function of the GYF domain of CD2BP2 in mediating protein-protein interactions within the spliceosome.

CD2BP2 (CD2 cytoplasmic tail binding protein 2), one of several proteins interacting with the cytoplasmic tail of CD2, plays a crucial role in CD2-triggered T cell activation and nuclear splicing. The studies on CD2BP2 have tended to be confined to a few mammals, and little information is available to date regarding fish CD2BP2. In this paper, a CD2BP2 gene (On-CD2BP2) was cloned from Nile tilapia, Oreochromis niloticus. Sequence analysis showed that the full length of On-CD2BP2 cDNA was 1429 bp, containing a 5'untranslated region (UTR) of 111 bp, a 3'-UTR of 193 bp and an open reading frame of 1125 bp which is encoding 374 amino acids. Two important structural features, a GYF domain and a consensus motif GPFXXXXMXXWXXXGYF were detected in the deduced amino acid sequence of On-CD2BP2, and the deduced genomic structure of On-CD2BP2 was similar to the known CD2BP2. The mRNA expression of On-CD2BP2 in various tissues of Nile tilapia was analyzed by fluorescent quantitative real-time PCR. In healthy Nile tilapia, the On-CD2BP2 transcripts were mainly detected in the head kidney and spleen. While vaccinated with inactivated Streptococcus agalactiae, the On-CD2BP2 mRNA expression was significantly up-regulated in the head kidney, spleen and brain 48 h post immunization. Moreover, there was a clear time-dependent expression pattern of On-CD2BP2 after immunization and the expression reached the highest level at 24 h in the brain and 48 h in the head kidney and spleen. This is the first report of proving the presence of a CD2BP2 ortholog in fish, and investigating its tissue distribution and expression profile in response to bacterial stimulus. These findings indicated that On-CD2BP2 may play an important role in the immune response to bacteria in Nile tilapia. (C) 2014 Elsevier B.V. All rights reserved.