Identification and characterization of a new kallikrein-kinin system inhibitor from the salivary glands of the malaria vector mosquito Anopheles stephensi.
A new kallikrein-kinin system inhibitor, designated anophensin, was identified in the salivary glands of the malaria vector mosquito, Anopheles stephensi. In vitro reconstitution experiments showed that anophensin inhibits activation of the kallikrein-kinin system by inhibiting the reciprocal activation of factor XII (FXII) and prekallikrein (PK), and subsequent release of bradykinin. Additionally, anophensin inhibits activation of the kallikrein-kinin system on cultured human umbilical vein endothelial cells (HUVECs). Direct binding assays show that this inhibitory effect is due to Zn(2+)-dependent specific binding of anophensin to both FXII and high molecular weight kininogen (HK). Furthermore, anophensin interacts with both the N-terminus of FXII and domain D5 of HK, which are the binding domains for biological activating surfaces. These results suggest that anophensin inhibits activation of the kallikrein-kinin system by interfering with the association of FXII and HK with biological activating surfaces, resulting in the inhibition of bradykinin release in a host animal during insect blood-feeding.
Isawa
Haruhiko
H
Department of Medical Entomology, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan. hisawa@nih.go.jp
Orito
Yuki
Y
Iwanaga
Shiroh
S
Jingushi
Naruhiro
N
Morita
Akihiro
A
Chinzei
Yasuo
Y
Yuda
Masao
M
D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000378:metabolism*; D001665:Binding Sites; D001920:Bradykinin / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D005174:Factor XII / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D007303:Insect Vectors / Q000378:metabolism*; D016234:Kallikrein-Kinin System / Q000187:drug effects*; D019679:Kininogen, High-Molecular-Weight / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012469:Salivary Glands / Q000378:metabolism; D016415:Sequence Alignment; D015032:Zinc / Q000378:metabolism
D018076:DNA, Complementary; D019476:Insect Proteins; D019679:Kininogen, High-Molecular-Weight; D005174:Factor XII; D015032:Zinc; D001920:Bradykinin