Limulus kexin: a new type of Kex2-like endoprotease specifically expressed in hemocytes of the horseshoe crab.
A Kex2-like protease was identified in hemocytes of the horseshoe crab (Tachypleus tridentatus), named limulus kexin, and a full-length cDNA was obtained from a hemocyte cDNA library. The deduced amino acid sequence contains 752 residues, composed of five domains with a signal sequence, a propeptide, a catalytic domain, a Ser/Thr-rich domain, and a transmembrane domain. The domain organization is very similar to that of the yeast Kex2 except that limulus kexin does not have a cytoplasmic tail. The catalytic domain exhibits striking sequence identities with those of furins, especially Drosophila furin1 (79%). Northern blotting showed specific expression of limulus kexin in hemocytes, suggesting the involvement in proteolytic processing of the granule components of hemocytes.
Kawabata
S
S
Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan. skawascb@mbox.nc.kyushu-u.ac.jp.
Saeki
K
K
Iwanaga
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006434:Hemocytes / Q000378:metabolism; D006737:Horseshoe Crabs / Q000378:metabolism*; D008969:Molecular Sequence Data; D043484:Proprotein Convertases; D029701:Saccharomyces cerevisiae Proteins; D013381:Subtilisins / Q000096:biosynthesis / Q000235:genetics*
D018076:DNA, Complementary; D029701:Saccharomyces cerevisiae Proteins; D043484:Proprotein Convertases; D013381:Subtilisins; C058751:KEX2 protein, S cerevisiae