Identification and Characterization of a Novel Human Collectin CL‐K1

Abstract

Collectins are a family of C‐type lectins with two characteristic structures, collagen like domains and carbohydrate recognition domains. They recognize carbohydrate antigens on microorganisms and act as host‐defense. Here we report the cloning and characterization of a novel collectin CL‐K1. RT‐PCR analyses showed CL‐K1 mRNA is present in all organs. The deduced amino acid sequence and the data from immunostaining of CL‐K1 cDNA expressing CHO cells revealed that CL‐K1 is expressed as a secreted protein. CL‐K1 is found in blood by immunoblotting and partial amino acid analyses. CL‐K1 showed Ca2+‐dependent sugar binding activity of fucose and weakly mannose but not N‐acetyl‐galactosamine, N‐acetyl‐glucosamine, or maltose, though mannose‐binding lectin (MBL) containing similar amino acid motif. CL‐K1 can recognize specially several bacterial saccharides due to specific sugar‐binding character. Elucidation of the role of two ancestor collectins of CL‐K1 and CL‐L1 could lead to see the biological function of collectin family.

Transcriptional expression levels of chicken collectins are affected by avian influenza A virus inoculation

“…However, the chicken genome did not seem to contain a homologue for the second pulmonary collectin SP-D. In addition, chicken collectins 1, 2 and 3 were found which resemble the mammalian collectin liver 1 (CL-L1) (Ohtani et al, 1999), collectin kidney 1 (CL-K1) (Keshi et al, 2006) and collectin placenta 1 (CL-P1) (Ohtani et al, 2001). The biological roles of CL-L1 and CL-K1 have not been determined yet, leaving no indication for a possible role of chicken collectins cCL-1 and cCL-2.…”

Collectin-11 detects stress-induced L-fucose pattern to trigger renal epithelial injury

“…The collagenous region of CL-11 contains a binding motif for the MBL-associated serine proteases MASP-1, MASP-2, and MASP-3 (3,8), whose functions can initiate the complement cascade but may also involve substrates other than complement (9,10). Like MBL, CL-11 can interact with the surfaces of bacteria, viruses, and fungi, which indicates a significant role for CL-11 in host defense (3,8,11). However, there are certain biological differences between CL-11 and MBL that could affect the respective roles of these molecules at different tissue sites.…”

Investigations on Collectin Liver 1

“…Three further collectins were more recently discovered by Wakamiya and co-workers, i.e. collectin liver 1 (CL-L1, also termed collectin 10) (6), collectin placenta 1 (CL-P1, also termed collectin 12) (7), and collectin kidney 1 (CL-K1, also termed collectin 11 or CL-11) (8). CL-P1 is a membrane protein resembling scavenger receptors (9).…”