Related Experiment Video
Updated: Aug 10, 2026
10:58
Protein WISDOM: A Workbench for In silico De novo Design of BioMolecules
Published on: July 25, 2013
Recombinant glycoproteins that inhibit complement activation and also bind the selectin adhesion molecules
C W Rittershaus1, L J Thomas, D P Miller
1Avant Immunotherapeutics, Inc., Needham, Massachusetts 02494-2725, USA.
The Journal of Biological Chemistry
|April 10, 1999
Summary
Engineered soluble complement receptor type 1 (sCR1) variants with sialyl-Lewisx (sLex) glycosylation exhibit dual functionality. These modified proteins retain complement inhibition while also binding selectins, impacting cell adhesion in vitro.
Area of Science:
- Biochemistry
- Immunology
- Glycobiology
Background:
- Soluble human complement receptor type 1 (sCR1) and its truncated variant sCR1[desLHR-A] inhibit complement pathways.
- These proteins were previously expressed in Chinese hamster ovary (CHO) DUKX-B11 cells, lacking alpha(1,3)-fucose.
- Sialyl-Lewisx (sLex) is a carbohydrate ligand for selectin adhesion molecules.
Purpose of the Study:
- To express sCR1 and sCR1[desLHR-A] in CHO LEC11 cells engineered for sLex biosynthesis.
- To evaluate the complement regulatory activity and selectin-binding capabilities of the resulting sLex-modified glycoproteins.
- To assess the impact of sLex incorporation on selectin-mediated cell adhesion.
Main Methods:
- Expression of sCR1 and sCR1[desLHR-A] in CHO LEC11 cells with active alpha(1,3)-fucosyltransferase.
- Characterization of sLex incorporation using carbohydrate analysis.
- In vitro assays to assess complement inhibition, E-selectin and P-selectin binding, and inhibition of cell adhesion.
Main Results:
- sCR1 and sCR1[desLHR-A] were successfully glycosylated with sLex, forming sCR1sLex and sCR1[desLHR-A]sLex.
- These modified glycoproteins retained their complement regulatory activities.
- sCR1sLex and sCR1[desLHR-A]sLex demonstrated binding to E-selectin and P-selectin, inhibiting selectin-mediated adhesion in vitro.
Conclusions:
- Engineered sCR1 variants with sLex glycosylation maintain complement inhibitory functions.
- The incorporation of sLex confers the ability to bind selectins and inhibit selectin-dependent cell adhesion.
- These dual-functional molecules offer potential therapeutic applications in inflammatory and immune-related conditions.
Related Concept Videos
01:21Matrix Proteoglycans and Glycoproteins
Proteoglycans are extensively glycosylated proteins, commonly found in the extracellular matrix, interwoven with collagen fibers. Hyaline cartilage, the most common type of cartilage in the body, consists of short and dispersed collagen fibers associated with large amounts of proteoglycans. These proteoglycans have long negative charges that attract cations, which in turn attract water molecules. This influx of ions and water molecules swells up the proteoglycan like a water-soaked gel that can...
01:10Integrins
Animal and protozoan cells do not have cell walls to help maintain shape and provide structural stability. Instead, these eukaryotic cells secrete a sticky mass of carbohydrates and proteins into the spaces between adjacent cells. This network of proteins and molecules is called an extracellular matrix or ECM.
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
01:15Activation of Integrins
Integrins bind ligands and transmit information from outside the cell to inside or vice-versa through an "outside-in signaling" or "inside-out signaling."
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
01:25Selectins
Cell adhesion is an essential aspect of multicellularity. While stable cell interactions usually occur between cells of the same type, transient cell interactions occur between cells of different tissue types, such as between neutrophils and endothelial cells. Selectins are one class of cell adhesion molecules (CAMs) that bind carbohydrate ligands to form transient cell adhesion. They are rod-like proteins with a long extracellular part of variable length ending with the lectin domain, which...
01:31Immunoglobulin-like Cell Adhesion Molecules
Immunoglobulin-like cell adhesion molecules or Ig-CAMs are a versatile group of cell surface glycoproteins belonging to the immunoglobulin protein superfamily. Ig-CAMs possess the characteristic immunoglobulin protein domains and other domains such as the fibronectin type III domain. The Ig domains are glycosylated to varying degrees in different Ig-CAMs.
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
01:27Complement System
The complement system is a group of approximately 20 plasma proteins that strengthen the body's defenses against infections through opsonization, inflammation, and cell lysis. Opsonization involves coating pathogens with complement proteins, making them more recognizable and facilitating phagocyte engulfment. Certain complement proteins induce inflammation that attracts immune cells to the site of infection. Cell lysis involves the destruction of pathogens through the formation of a membrane...