C1QA

Background

Complement C1q subcomponent subunit A (C1QA) is a constituent of the complement component C1q (a subunit of the first complement component C1). Human C1QA is a 28 kDa polypeptide chain with 244 amino acids forming a lollipop-shaped structure, of which 81 amino acids form a long collagen-like N-terminal "stalk" and 136 amino acids form a characteristic spherical "head". C1QA polypeptide chain is connected to C1QB chain by disulfide bond forming an A-B or B-A doublet, whereas, C1QC is connected to adjacent C chain by a disulfide bond forming a C-C doublet. These disulfide-linked doublets are noncovalently linked to form a ‘bouquet-of-flowers’ like hexamer structure, that is intact complement component C1q.

C1QA functions as a sub-chain of complement C1q, which together with C1q form the complement C1 complex. When antigen-antibody complexes are formed, the 6 triple helical strands of C1q can bind to the Fc domains of antibodies, such as IgM and IgG (except IgG4), leading to the activation of the complement classical pathway. C1QA abnormality causes C1q deficiency, complement dysfunction, and immunodeficiency.

Fig.1 Structure and composition of the c1q subunit.^{1, 3}

C1QA Functional Service

Creative Biolabs offers an extensive array of C1QA-specific products, encompassing anti-C1QA antibodies, ELISA kits, recombinant C1QA proteins, and reporter vectors containing C1QA clones. These meticulously designed reagents play a pivotal role in elucidating the interactions between C1QA proteins and various molecular structures, thereby advancing research efforts focused on developing therapeutic strategies for a wide range of diseases.

Fig.2 Analysis of expression levels and prognostic implications of C1QA, C1QB, and C1QC in SKCM.^{2, 3}

Skin cutaneous melanoma (SKCM) represents a common form of cancer, characterized by notable rates of morbidity and mortality. In order to investigate how the complement components C1QA, C1QB, and C1QC contribute to tumor progression and immune response in SKCM, researchers have employed GEPIA, TIMER, RT-qPCR, and GEO datasets to explore expression levels and prognostic implications, followed by the creation of nomograms and assessment of immune interactions. Elevated expressions of C1QA, C1QB, and C1QC are associated with enhanced survival rates in SKCM, acting as independent prognostic markers. Their expression is linked with immune infiltration and pathway enrichment, potentially improving the efficacy of immunotherapy through mechanisms involving tumor suppression and apoptosis.

Creative Biolabs offers a suite of services focused on C1QA functionality, encompassing C1QA-binding assays and other specialized functional assessments, meticulously designed to support our esteemed clients in their clinical and research endeavors.