Parotid secretory protein is an HDL-associated protein with anticandidal activity.
High-density lipoprotein (HDL) is part of innate immunity, protecting against infection and inflammation. Using a proteomic approach, we identified an amino acid sequence in a hamster HDL protein that showed homology to rat and mouse parotid secretory protein (PSP), a salivary protein secreted from the parotid glands. We cloned the cDNA encoding a putative hamster homolog of rat and mouse PSP. Searches for conserved domains of the protein showed that the COOH terminus of hamster PSP contains a region homologous to the NH2 termini of a family of HDL-associated proteins, including LPS-binding protein, cholesteryl ester transfer protein, and phospholipid transfer protein. In mice, PSP was also associated with HDL but was not detected in very-low-density lipoprotein, low-density lipoprotein, or lipoprotein-deficient sera. In addition to salivary glands, we found that PSP mRNA was expressed in lung, testis, and ovary. The level of PSP in HDL was increased after endotoxin injection in hamsters, but not in mice. Recombinant PSP inhibits growth of Candida albicans in culture. In summary, our results showed that PSP is a novel anticandidal protein associated with HDL.
Khovidhunkit
Weerapan
W
Metabolism Sect., Dept. of Veterans Affairs Medical Center, 4150 Clement St., Box 111 F, San Francisco, CA 94121, USA.
Hachem
Jean Pierre
JP
Medzihradszky
Katalin F
KF
Duchateau
Philippe N
PN
Shigenaga
Judy K
JK
Moser
Arthur H
AH
Movsesyan
Irina
I
Naya-Vigne
Josefina
J
Kane
John P
JP
Feingold
Kenneth R
KR
Grunfeld
Carl
C
D000595:Amino Acid Sequence; D000818:Animals; D002176:Candida albicans / Q000276:immunology*; D006224:Cricetinae; D004731:Endotoxins; D015870:Gene Expression; D007113:Immunity, Innate; D008075:Lipoproteins, HDL / Q000097:blood* / Q000737:chemistry / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D051381:Rats; D012469:Salivary Glands / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000097:blood* / Q000737:chemistry / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
C511597:Bpifa2 protein, mouse; C511598:Bpifa2 protein, rat; D004731:Endotoxins; D008075:Lipoproteins, HDL; D012471:Salivary Proteins and Peptides