Product List

CD55 Human

CD55 Human Recombinant

CD55 produced in Sf9 Baculovirus cells is a single, glycosylated polypeptide chain (35-353 a.a.) and fused to a 9 aa His Tag at C-terminus containing a total of 328 amino acids and having a molecular mass of 36kDa. CD55 shows multiple bands between 40-57kDa on SDS-PAGE, reducing conditions and purified by proprietary chromatographic techniques.

Shipped with Ice Packs
Cat. No.
BT30442
Source
Sf9, Baculovirus cells.
Appearance
Sterile Filtered colorless solution.

CD55 Mouse

CD55 Mouse Recombinant

CD55 produced in Sf9 Baculovirus cells is a single, glycosylated polypeptide chain containing 336 amino acids (35-362 a.a.) and having a molecular mass of 36.8kDa (Migrates at 40-57kDa on SDS-PAGE under reducing conditions).
CD55 is expressed with an 8 amino acid His tag at C-Terminus and purified by proprietary chromatographic techniques.
Shipped with Ice Packs
Cat. No.
BT30470
Source
Sf9, Baculovirus cells.
Appearance
Sterile Filtered colorless solution.

Introduction

Definition and Classification

CD55, also known as Decay-Accelerating Factor (DAF), is a glycoprotein encoded by the CD55 gene. It is a member of the complement regulatory proteins and plays a crucial role in regulating the complement system on the cell surface . CD55 is classified under the Cromer blood group system and is involved in preventing damage to host cells by accelerating the decay of complement proteins .

Biological Properties

Key Biological Properties: CD55 is a 70 kDa membrane protein that attaches to the cell membrane via a glycophosphatidylinositol (GPI) anchor . It contains four complement control protein (CCP) repeats with a single N-linked glycan positioned between CCP1 and CCP2 .

Expression Patterns and Tissue Distribution: CD55 is broadly distributed among hematopoietic and non-hematopoietic cells. It is highly expressed in most epithelial cells, trophoblasts, and alveolar cells, with distinct positivity in connective tissue . It is also a determinant for the Cromer blood group system .

Biological Functions

Primary Biological Functions: CD55 regulates the complement system by recognizing C4b and C3b fragments created during the activation of C4 and C3 . It interferes with the conversion of C2 to C2b and factor B to Bb, thereby preventing the formation of C4b2a and C3bBb, the amplification convertases of the complement cascade . This inhibition prevents complement damage to host cells .

Role in Immune Responses and Pathogen Recognition: CD55 plays a critical role in immune responses by preventing the formation of the membrane attack complex, thereby protecting cells from complement-mediated lysis . It is also used as a receptor by some coxsackieviruses and other enteroviruses .

Modes of Action

Mechanisms with Other Molecules and Cells: CD55 interacts with cell-associated C4b and C3b polypeptides, interfering with their ability to catalyze the conversion of C2 and factor B to enzymatically active C2a and Bb . This interaction prevents the formation of C4b2a and C3bBb, the amplification convertases of the complement cascade .

Binding Partners and Downstream Signaling Cascades: CD55 modulates Toll-like receptor 9 (TLR9) signaling and supports the survival of marginal zone B cells . It also traffics to the nucleus in certain cancer cells, leading to cisplatin resistance and stemness by inducing PRC2 and H3K27 trimethylation on chromatin .

Regulatory Mechanisms

Regulatory Mechanisms Controlling Expression and Activity: CD55 expression is regulated by transcription factors such as TFCP2 and NF-κB, as well as miRNAs like miR-27a-3p . Post-translational modifications, such as glycosylation, also play a role in its function and localization .

Transcriptional Regulation and Post-Translational Modifications: The promoter activity of CD55 is influenced by TFCP2 and NF-κB binding sites . Glycosylation of CD55 is necessary for its nuclear entry and function in chemoresistant cancer cells .

Applications

Biomedical Research: CD55 is used in various scientific applications, including flow cytometry, Western blot, immunohistochemistry, immunocytochemistry, and ELISA .

Diagnostic Tools and Therapeutic Strategies: CD55 antibodies are used to detect its presence in human, mouse, non-human primate, and rat samples . Targeting CD55 has potential therapeutic applications in treating chemoresistant cancers and preventing complement-mediated damage in autoimmune diseases .

Role in the Life Cycle

Role Throughout the Life Cycle: CD55 plays a role in various stages of life, from development to aging and disease. It is expressed by neurons in response to chronic autoimmune central nervous system inflammation . In cancer, CD55 contributes to chemoresistance and the maintenance of cancer stem cells, which are implicated in tumor recurrence and metastasis .

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