Molecular and functional analysis of PmC1qDC in nacre formation of Pinctada fucata martensii

Invertebrate C1q Domain-Containing Proteins: Molecular Structure, Functional Properties and Biomedical Potential

“…An exception is PmC1qDC-1, for which the authors attribute high transcriptional activity at key stages of shell formation. This suggestion is related to a more detailed study of PmC1qDC-1 in terms of its effect on the formation of the shell and its recovery after notching [54,96]. Notably, a group of proteins called KEYSTONEin from Mytilus californianus and M. galloprovincialis, in addition to a similar role in shell formation, has also been shown to play a role as a chemoattractant for predatory starfish, which extends the C1qDC value to an interspecies relation [109].…”

“…Many experimental articles devoted to C1qDC proteins present their phylogenetic trees [25,36,40,41,43,[45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60]. Phylogenetic trees do not reflect the actual evolution of the C1qDC family of proteins for several reasons.…”

“…Even in a 2010 review, a high similarity of the tertiary structure of C1q domains was noted in phylogenetically very distant organisms, such as bacteria, mussels, and humans [38]. A characteristic jelly roll topology consisting of a ten-strand β-sandwich has been identified for CfC1qDC and CfC1qDC-2 from C. farreri [46,86], AiC1qDC-1 and AiC1qDC-2 from A. irradians [47,87], PmC1qDC from P. fucata [54], and BsC1qDC from Botryllus schlosseri [45], as well as an eight-strand β-sandwich for CgC1qDC-1 from C. gigas (M. gigas) [88]. At the same time, usually they show a low degree of identity with the amino acid sequences of human C1q domains, which were used as a reference [45,47,86,87].…”

“…At the same time, usually they show a low degree of identity with the amino acid sequences of human C1q domains, which were used as a reference [45,47,86,87]. However, in all cases, conservative aromatic amino acids involved in the formation of the hydrophobic part of the C1q domains, as well as some charged amino acids important for the structure, were identified [45][46][47]54,[86][87][88].…”

A Novel C1q Domain-Containing Protein Isolated from the Mollusk Modiolus kurilensis Recognizing Glycans Enriched with Acidic Galactans and Mannans

“…Presumably, the abundance of C1qDC proteins allows covering the protective needs of the bivalve against various pathogens due to the potential structural diversity of PAMPs. Many bivalve C1qDC proteins are soluble, secreting PRRs that agglutinate and opsonize foreign agents by PAMPs recognizing [8][9][10][11][12], but several studies also have shown that they are involved in embryogenesis [9,10,13], shell formation [14][15][16] and interaction with predators [14]. Until recent years, some bivalve C1qDC proteins are classified either as lectins [8,[17][18][19] or as lectin-like proteins, which emphasizes their probable origin as lectins with subsequent diversification [2,7,20].…”