Surfactant protein D, also known as SP-D, is a
lung surfactant protein part of the collagenous family of lectins called
collectin.
In humans, SP-D is encoded by the ''SFTPD''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
and is part of the
innate immune system
The innate immune system or nonspecific immune system is one of the two main immunity strategies in vertebrates (the other being the adaptive immune system). The innate immune system is an alternate defense strategy and is the dominant immune s ...
.
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 with
DMBT1,
and
hemagglutinin
The term hemagglutinin (alternatively spelt ''haemagglutinin'', from the Greek , 'blood' + Latin , 'glue') refers to any protein that can cause red blood cells (erythrocytes) to clump together (" agglutinate") ''in vitro''. They do this by bindin ...
of
influenza A virus
''Influenza A virus'' (''Alphainfluenzavirus influenzae'') or IAV is the only species of the genus ''Alphainfluenzavirus'' of the virus family '' Orthomyxoviridae''. It is a pathogen with strains that infect birds and some mammals, as well as c ...
. 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 cells, type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions. By adsorption, adso ...
*
Pulmonary surfactant protein D
References
Further reading
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External links
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Collectins
Long stubs with short prose
{{Protein-stub