scholarly journals The structure and function of surfactant protein A. Hydroxyproline- and carbohydrate-deficient mutant proteins.

1994 ◽  
Vol 269 (8) ◽  
pp. 5833-5841
Author(s):  
F.X. McCormack ◽  
H.M. Calvert ◽  
P.A. Watson ◽  
D.L. Smith ◽  
R.J. Mason ◽  
...  
Keyword(s):  
Protein A ◽  
Surfactant Protein ◽  
Structure And Function ◽  
Surfactant Protein A ◽  
Deficient Mutant ◽  
Mutant Proteins ◽  
And Function

scholarly journals Role of the Degree of Oligomerization in the Structure and Function of Human Surfactant Protein A

2004 ◽  
Vol 280 (9) ◽  
pp. 7659-7670 ◽  
Author(s):  
Fernando Sánchez-Barbero ◽  
Jochen Strassner ◽  
Rafael García-Cañero ◽  
Wolfram Steinhilber ◽  
Cristina Casals
Keyword(s):  
Protein A ◽  
Surfactant Protein ◽  
Structure And Function ◽  
Surfactant Protein A ◽  
And Function

scholarly journals Characterization of the Ca2+-dependent binding of annexin IV to surfactant protein A

1999 ◽  
Vol 341 (1) ◽  
pp. 203-209 ◽  
Author(s):  
Hitoshi SOHMA ◽  
Carl E. CREUTZ ◽  
Masaki SAITOH ◽  
Hitomi SANO ◽  
Yoshio KUROKI ◽  
...  
Keyword(s):  
Protein A ◽  
Surfactant Protein ◽  
The Other ◽  
Site Directed Mutagenesis ◽  
Surfactant Protein A ◽  
Dependent Manner ◽  
Mutant Proteins ◽  
Truncation Mutant ◽  
Domain 3 ◽  
Annexin Iv

We have shown previously that surfactant protein A (SP-A) binds to annexin IV in a Ca2+-dependent manner [Sohma, Matsushima, Watanabe, Hattori, Kuroki and Akino (1995) Biochem. J. 312, 175-181]. Annexin IV is a member of the annexin family having four consensus repeats of about 70 amino acids and a unique N-terminal tail. In the present study, the functional site of both annexin IV and SP-A for the Ca2+-dependent binding was investigated using mutant proteins. SP-A bound in a Ca2+-dependent manner to an annexin-IV truncation mutant consisting of the N-terminal domain and the first three domains (TN-1-2-3). SP-A also bound to T3-4, but this interaction was not Ca2+-dependent. SP-A bound weakly to the other truncation mutants (TN-1-2, T2-3 and T2-3-4). Each consensus repeat of annexin IV possesses a conserved acidic amino acid residue (Glu70, Asp142, Glu226 and Asp301) that putatively ligates Ca2+. Using annexin-IV DE mutants in which one, two or three residues out of the four Asp/Glu were altered to Ala by site-directed mutagenesis [Nelson and Creutz (1995) Biochemistry 34, 3121-3132], it was revealed that Ca2+ binding in the third domain is more important than in the other Ca2+-binding sites. SP-A is a member of the animal lectin group homologous with mannose-binding protein A. The substitution of Arg197 of rat SP-A with Asp or Asn eliminated binding to annexin IV, whereas the substitution of Glu195 with Gln was silent. These results suggest that the Ca2+ binding to domain 3 of annexin IV is required for the Ca2+-dependent binding by SP-A and that Arg197 of SP-A is important in this binding.

scholarly journals Surfactant Protein-A Function: Knowledge Gained From SP-A Knockout Mice

2022 ◽  
Vol 9 ◽  
Author(s):  
Lynnlee Depicolzuane ◽  
David S. Phelps ◽  
Joanna Floros
Keyword(s):  
Oxidative Stress ◽  
Host Defense ◽  
Protein A ◽  
Infectious Agent ◽  
Surfactant Protein ◽  
Alveolar Epithelial Cells ◽  
Surfactant Protein A ◽  
Alveolar Epithelial ◽  
Pulmonary Surfactant Proteins ◽  
And Function

Pulmonary surfactant proteins have many roles in surfactant- related functions and innate immunity. One of these proteins is the surfactant protein A (SP-A) that plays a role in both surfactant-related processes and host defense and is the focus in this review. SP-A interacts with the sentinel host defense cell in the alveolus, the alveolar macrophage (AM), to modulate its function and expression profile under various conditions, as well as other alveolar epithelial cells such as the Type II cell. Via these interactions, SP-A has an impact on the alveolar microenvironment. SP-A is also important for surfactant structure and function. Much of what is understood of the function of SP-A and its various roles in lung health has been learned from SP-A knockout (KO) mouse experiments, as reviewed here. A vast majority of this work has been done with infection models that are bacterial, viral, and fungal in nature. Other models have also been used, including those of bleomycin-induced lung injury and ozone-induced oxidative stress either alone or in combination with an infectious agent, bone marrow transplantation, and other. In addition, models investigating the effects of SP-A on surfactant components or surfactant structure have contributed important information. SP-A also appears to play a role in pathways involved in sex differences in response to infection and/or oxidative stress, as well as at baseline conditions. To date, this is the first review to provide a comprehensive report of the functions of SP-A as learned through KO mice.

scholarly journals Surfactant protein A reduces TLR4 and inflammatory cytokine mRNA levels in neonatal mouse ileum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lidan Liu ◽  
Chaim Z. Aron ◽  
Cullen M. Grable ◽  
Adrian Robles ◽  
Xiangli Liu ◽  
...  
Keyword(s):  
Proinflammatory Cytokine ◽  
Inflammatory Cytokine ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Mrna Levels ◽  
Wild Type ◽  
Cytokine Mrna ◽  
Protein Levels ◽  
Cytokine Levels

AbstractLevels of intestinal toll-like receptor 4 (TLR4) impact inflammation in the neonatal gastrointestinal tract. While surfactant protein A (SP-A) is known to regulate TLR4 in the lung, it also reduces intestinal damage, TLR4 and inflammation in an experimental model of necrotizing enterocolitis (NEC) in neonatal rats. We hypothesized that SP-A-deficient (SP-A−/−) mice have increased ileal TLR4 and inflammatory cytokine levels compared to wild type mice, impacting intestinal physiology. We found that ileal TLR4 and proinflammatory cytokine levels were significantly higher in infant SP-A−/− mice compared to wild type mice. Gavage of neonatal SP-A−/− mice with purified SP-A reduced ileal TLR4 protein levels. SP-A reduced expression of TLR4 and proinflammatory cytokines in normal human intestinal epithelial cells (FHs74int), suggesting a direct effect. However, incubation of gastrointestinal cell lines with proteasome inhibitors did not abrogate the effect of SP-A on TLR4 protein levels, suggesting that proteasomal degradation is not involved. In a mouse model of experimental NEC, SP-A−/− mice were more susceptible to intestinal stress resembling NEC, while gavage with SP-A significantly decreased ileal damage, TLR4 and proinflammatory cytokine mRNA levels. Our data suggests that SP-A has an extrapulmonary role in the intestinal health of neonatal mice by modulating TLR4 and proinflammatory cytokines mRNA expression in intestinal epithelium.

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