Analysis of Plasma Proteins Encoded by the X-chromosome Vniranjan, Rmahmood, M.balamurugan, Nitesh

Plasma proteins are the most important proteins of human body and include enzymes, regulatory proteins, clotting factors and hormones. They perform diverse functions in the human body and play a cardinal role in its normal functioning. An aberration in structure, function or concentration of even one plasma protein may have fatal consequences. As a result, the study of plasma proteins becomes imperative to gain an insight into the reasons underlying various disorders which may be attributed to an anomaly in structure, function or variation in number of different types of plasma proteins. With the view to acquire information about the various proteins present in the blood plasma and to analyze the functions of all these proteins, a comprehensive analysis of plasma proteins was carried out. Each protein was analyzed individually on various parameters namely the number of isoforms of that protein, the number of Single Nucleotide Polymorphisms (SNPs) present, the ectopic localization, post translational modifications(PTMs), proteolytic cleavage and expressions. Thus, a detailed and extensive analysis of each protein was carried out and this was followed by comparative analysis of all the plasma proteins. The proteins for which the locus was found to be on X-chromosome were studied for further analysis and studied for the presence of isoforms. SNPs were found in 47% of the X-chromosomal plasma proteins. PTM analysis revealed that only 6% of these proteins showed post translational modifications. No proteolytic cleavages were found. The ectopic localization of 62% of the plasma proteins is still not known, while a considerable percentage of proteins were found to be localized in the nucleus and cytoplasm. Only a small proportion of the proteins were found to be located on the plasma membrane and much lesser on the extracellular surface. The presence of a high percentage of X-chromosomal plasma proteins in nucleus and cytoplasm illustrates explicitly a deviation in the localization of plasma proteins. The data obtained indicates a leakage or malfunctioning of these proteins. Hence, we believe that the region of the X chromosome coding for these plasma proteins fall among the other important disease susceptible regions of the X chromosome.