Surfactant protein D, also known as SP-D, is a
lung surfactant protein part of the collagenous family of proteins called
collectin Collectins (collagen-containing C-type lectins) are a part of the innate immune system. They form a family of collagenous Ca2+-dependent defense lectins, which are found in animals. Collectins are soluble pattern recognition receptors (PRRs). Their ...
.
In humans, SP-D is encoded by the ''SFTPD''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
and is part of the
innate immune system
The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the ...
.
Each SP-D subunit is composed of an N-terminal domain, a
collagenous region, a nucleating neck region, and a C-terminal lectin domain.
Three of these subunits assemble to form a homotrimer, which further assemble into a tetrameric complex.
Interactions
Surfactant protein D has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...
with
DMBT1
Deleted in malignant brain tumors 1 protein is a protein that in humans is encoded by the ''DMBT1'' gene.
Function
Loss of sequences from human chromosome 10q has been associated with the progression of human cancers. The gene DMBT1 was origi ...
,
and
hemagglutinin
In molecular biology, hemagglutinins (or ''haemagglutinin'' in British English) (from the Greek , 'blood' + Latin , 'glue') are receptor-binding membrane fusion glycoproteins produced by viruses in the ''Paramyxoviridae'' family. Hemagglutinins ar ...
of
influenza A virus
''Influenza A virus'' (''IAV'') causes influenza in birds and some mammals, and is the only species of the genus ''Alphainfluenzavirus'' of the virus family ''Orthomyxoviridae''. Strain (biology)#Microbiology or virology, Strains of all subtypes ...
. Post-translational modification of SP-D i.e. S-nitrosylation switches its function.
See also
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pulmonary surfactant
Pulmonary surfactant is a surface-active complex of phospholipids and proteins formed by type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic
In chemistry, hydrophobicity is t ...
References
Further reading
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External links
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Collectins
{{Protein-stub