TY - JOUR
T1 - Tracing the Evolutionary History of the CAP Superfamily of Proteins Using Amino Acid Sequence Homology and Conservation of Splice Sites
AU - Abraham, Anup
AU - Chandler, Douglas E.
N1 - Funding Information:
Stuart Newfeld for advice on phylogenetic tree construction. We would also like to thank the National Science Foundation for support of our previous studies of allurin, a truncated CRISP protein having sperm chemoattractant activity, which led to our interest in the evolution of CAP proteins.
Publisher Copyright:
© 2017, Springer Science+Business Media, LLC.
PY - 2017/10/1
Y1 - 2017/10/1
N2 - Proteins of the CAP superfamily play numerous roles in reproduction, innate immune responses, cancer biology, and venom toxicology. Here we document the breadth of the CAP (Cysteine-RIch Secretory Protein (CRISP), Antigen 5, and Pathogenesis-Related) protein superfamily and trace the major events in its evolution using amino acid sequence homology and the positions of exon/intron borders within their genes. Seldom acknowledged in the literature, we find that many of the CAP subfamilies present in mammals, where they were originally characterized, have distinct homologues in the invertebrate phyla. Early eukaryotic CAP genes contained only one exon inherited from prokaryotic predecessors and as evolution progressed an increasing number of introns were inserted, reaching 2–5 in the invertebrate world and 5–15 in the vertebrate world. Focusing on the CRISP subfamily, we propose that these proteins evolved in three major steps: (1) origination of the CAP/PR/SCP domain in bacteria, (2) addition of a small Hinge domain to produce the two-domain SCP-like proteins found in roundworms and anthropoids, and (3) addition of an Ion Channel Regulatory domain, borrowed from invertebrate peptide toxins, to produce full length, three-domain CRISP proteins, first seen in insects and later to diversify into multiple subtypes in the vertebrate world.
AB - Proteins of the CAP superfamily play numerous roles in reproduction, innate immune responses, cancer biology, and venom toxicology. Here we document the breadth of the CAP (Cysteine-RIch Secretory Protein (CRISP), Antigen 5, and Pathogenesis-Related) protein superfamily and trace the major events in its evolution using amino acid sequence homology and the positions of exon/intron borders within their genes. Seldom acknowledged in the literature, we find that many of the CAP subfamilies present in mammals, where they were originally characterized, have distinct homologues in the invertebrate phyla. Early eukaryotic CAP genes contained only one exon inherited from prokaryotic predecessors and as evolution progressed an increasing number of introns were inserted, reaching 2–5 in the invertebrate world and 5–15 in the vertebrate world. Focusing on the CRISP subfamily, we propose that these proteins evolved in three major steps: (1) origination of the CAP/PR/SCP domain in bacteria, (2) addition of a small Hinge domain to produce the two-domain SCP-like proteins found in roundworms and anthropoids, and (3) addition of an Ion Channel Regulatory domain, borrowed from invertebrate peptide toxins, to produce full length, three-domain CRISP proteins, first seen in insects and later to diversify into multiple subtypes in the vertebrate world.
KW - CRISP protein family
KW - Cysteine-rich protein superfamily
KW - Phylogenetic analysis
KW - Splice sites
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U2 - 10.1007/s00239-017-9813-9
DO - 10.1007/s00239-017-9813-9
M3 - Article
C2 - 29071358
AN - SCOPUS:85032221952
SN - 0022-2844
VL - 85
SP - 137
EP - 157
JO - Journal of Molecular Evolution
JF - Journal of Molecular Evolution
IS - 3-4
ER -