MUC16/CA125 in the Context of Modular Proteins with an Annotated Role in Adhesion-Related Processes: In Silico Analysis

Abstract

Mucin 16 (MUC16) is a type I transmembrane protein, the extracellular portion of which is shed after proteolytic degradation and is denoted as CA125 antigen, a well known tumor marker for ovarian cancer. Regarding its polypeptide and glycan structures, as yet there is no detailed insight into their heterogeneity and ligand properties, which may greatly influence its function and biomarker potential. This study was aimed at obtaining further insight into the biological capacity of MUC16/CA125, using in silico analysis of corresponding mucin sequences, including similarity searches as well as GO (gene ontology)-based function prediction. The results obtained pointed to the similarities within extracellular serine/threonine rich regions of MUC16 to sequences of proteins expressed in evolutionary distant taxa, all having in common an annotated role in adhesion-related processes. Specifically, a homology to conserved domains from the family of herpesvirus major outer envelope protein (BLLF1) was found. In addition, the possible involvement of MUC16/CA125 in carbohydrate-binding interactions or cellular transport of protein/ion was suggested.

CA-125 of fetal origin can act as a ligand for dendritic cell-specific ICAM-3-grabbing non-integrin

“…As for the protein backbone, CA-125 homology to conserved domains from the outer envelope protein of the Herpesviridae family was found. This is the major antigen responsible for the production of neutralizing antibodies in vivo [36]. Moreover, it is known that DC-SIGN has the capacity to bind various viral envelope proteins, but these interactions are not strictly defined.…”