Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara
Automatic assignment of GO terms using logical inference, based on on inter-ontology links
Substrate specificities of recombinant mannan-binding lectin-associated serine proteases-1 and -2.
Modular organization of the carboxyl-terminal, globular head region of human C1q A, B, and C chains.
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Human recombinant MBP-ghA binds heat-aggregated immunoglobulins, directly supporting an A-chain contribution to recognition. The complete cached abstract was read; full Methods were unavailable.
"the MBP-ghA bound to heat-aggregated IgG and IgM"
The crystal structure of the globular head of complement protein C1q provides a basis for its versatile recognition properties.
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The human C1q globular-head crystal structure establishes noncovalent heterotrimer assembly, independently supporting chain association beyond the A-B disulfide linkage. The complete abstract was read.
"assembly held together mainly by non-polar interactions"
Absence of C1q leads to less neuropathology in transgenic mouse models of Alzheimer's disease.
C1q binds phosphatidylserine and likely acts as a multiligand-bridging molecule in apoptotic cell recognition.
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The phosphoserine crystal contact is principally on chain C. C1QA contributes within the assembled recognition head; this is not evidence for an autonomous A-chain phosphatidylserine-binding site.
"phosphoserine is bound to subunit C"
Interaction of human C1q with IgG and IgM: revisited.
CD91 interacts with mannan-binding lectin (MBL) through the MBL-associated serine protease-binding site.
Toward an understanding of the protein interaction network of the human liver.
Expression of recombinant human complement C1q allows identification of the C1r/C1s-binding sites.
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Recombinant human C1q binds the C1r/C1s assembly and supports its activation. C1QA contributes recognition and assembly while C1r/C1s carry the protease activities; this reading is limited to the complete abstract.
"to trigger C1r and
C1s activation"
Complement is activated by IgG hexamers assembled at the cell surface.
Analysis of the Interaction between Globular Head Modules of Human C1q and Its Candidate Receptor gC1qR.
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Recombinant human ghA, ghB and ghC interact separately with mature gC1qR in the reported in vitro assays. This supports the exact processed binding partner without asserting a universal native receptor mechanism.
"ghA,
ghB, and ghC modules can interact with gC1qR independently"
Structure and activation of C1, the complex initiating the classical pathway of the complement cascade.
Evidence for C1q-mediated crosslinking of CD33/LAIR-1 inhibitory immunoreceptors and biological control of CD33/LAIR-1 expression.
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Whole C1q and its globular region bind CD33 and activate inhibitory motifs in the tested human monocyte context. This supports contributed receptor-ligand activity rather than isolated A-chain sufficiency.
"C1q and gC1q interact with CD33 to activate its
inhibitory motifs"
Characterization of the Extracellular Matrix of Normal and Diseased Tissues Using Proteomics.
Structures of C1-IgG1 provide insights into how danger pattern recognition activates complement.
Molecular modelling of human complement subcomponent C1q and its complex with C1r2C1s2 derived from neutron-scattering curves and hydrodynamic properties.
A reference map of the human binary protein interactome.
The binding site for C1q on IgG.
C1q binding to surface-bound IgG is stabilized by C1r(2)s(2) proteases.
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Associated C1r2s2 proteases enhance whole-C1q avidity on surface-bound IgG. This supports recognition-complex function rather than protease catalysis by C1QA.
"C1r2s2
proteases affect the capacity of C1q to form an avid complex"
SARS-CoV-2 Exacerbates COVID-19 Pathology Through Activation of the Complement and Kinin Systems.
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The Figure 5 caption identifies recombinant ghA as the positive control in the gC1qR binding assay. The caption and relevant narrative were inspected; the figure image was not.
"Positive control for binding is ghA"
Activation of a complex of C1r and C1s subcomponents of human complement C1 by the third subcomponent C1q.
The Clq receptor site on immunoglobulin G.
Ultrastructure of the first component of human complement: electron microscopy of the crosslinked complex.
Isolation, by partial pepsin digestion, of the three collagen-like regions present in subcomponent Clq of the first component of human complement.
C1q-mediated chemotaxis by human neutrophils: involvement of gClqR and G-protein signalling mechanisms.
Conversion of C4 into C4a and C4b
Conversion of C2 into C2a and C2b
C1-Inh binds Antigen: antibody: C1 complex activated C1r, C1s
Antigen:IgG:C1Q:2xActivated C1R:SERPING1:2xActivated C1S:SERPING1 dissociates
C1-Inh binds and inactivates C1r, C1s
UniProt P02745 C1QA record
The classical complement cascade mediates CNS synapse elimination.
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The complete cached abstract reports postnatal synaptic C1q localization and mouse C1q/C3-loss effects on retinogeniculate refinement. Full Methods were unavailable, so no uninspected detailed donor protocol is inferred.
"is localized to
synapses throughout the postnatal CNS and retina"
Complement and microglia mediate early synapse loss in Alzheimer mouse models.
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Structured illumination microscopy demonstrates C1q colocalization with PSD95-positive puncta in young Alzheimer-model mouse hippocampus. This supports postsynaptic localization without independently resolving every fine membrane or synapse-subtype term.
"SIM demonstrated colocalization of C1q with PSD95-positive puncta"