Surfactant apoprotein

S.L. Katyal and G. Singh, Analysis of pulmonary surfactant apoproteins by electrophoresis, Biochem. Biophys. Acta 670 (1981)323-331. 

Surfactant apoprotein A (SP-A) PE-10 Surfactant A Surfactant apoproteins isolated from lung lavages of patients with alveolar proteinosis Dako 1 100 HIER... 

A variety of epithelial cell markers (carcinoembry-onic antigen [CEA], human milk fat globule protein-2 [HMFG-2], epithelial membrane antigen [EMA], LeuMl [CD15], B72.3, BerEP4, and surfactant apoprotein) are... 

Type of Neoplasm CK5/6 CK7 CK20 Carcinoembryonic antigen Surfactant apoprotein A TTF-1 CDX2... 

Zamecnik J, Kodet R. Value of thyroid transcription factor-1 and surfactant apoprotein A in tbe differential diagnosis of pulmonary carcinomas a study of 109 cases. Virchows Arch. 2002 440 353-361. 

Singh G, Katyal SL, Bedrossian CW, et al. Pulmonary alveolar proteinosis. Staining for surfactant apoprotein in alveolar proteinosis and in conditions simulating it. Chest 1983 83(l) 82-86. 

Auten RL, Watkin RM, Shapiro DL, Horowitz S. Surfactant apoprotein A (SP-A) is synthetized in airway cells. Am J Respir Cell Mol Biol 1990 3 491-496. 

Walker SR, Williams MC, Benson B. Immunocytochemical localization of the major surfactant apoproteins in type II cells, Clara cells and alveolar macrophages of rat lung. J Histochem Cytochem 1986 34 1137-1148. 

Pison U, Wright J, Hawgood S. Specific binding of surfactant apoprotein SP-A to rat alveolar macrophages. Am J Physiol 1992 262 L412-L417. 

That is, nonionic surfactants caused an increase in the Stokes radius (R) of the particles due to penetration of the phospholipid surface layer and unfolding of apoprotein B molecules leading to particle assymetry at molar ratios of surfactant LDL2 of ca. 1000/1. At higher molar ratios, corresponding to 1-2 moles surfactant per mole of phospholipid, ionic surfactants and nonionics with HLB values < 14.6 caused rapid decreases in the Stokes radius due to breakdown of LDL2 into the lipid surfactant and protein surfactant micelles. 

Hawgood S, Clements JA. Pulmonary surfactant and its apoproteins. J Clin Invest 1990 86 1-6. 

Nonmucinous bronchioloalveolar cell carcinomas frequently show intranuclear inclusions that are PAS-diastase-positive " (Fig. 12.35). The intranuclear PAS-positive inclusions immunostain for the apoprotein portion of surfactant (Fig. 12.36). When examined ultrastructurally, these intranuclear inclusions consist of 45-nm-diameter tubules that attach to the inner nuclear membrane (Fig. 12.37). 

FIGURE 12.36 The intranuclear inclusions in nonmucinous bronchioloalveolar cell carcinomas immunostain for the apoprotein portion of surfactant A. X 400. 

Singh G, Katyal SL, Torikata C. Carcinoma of type II pneumo-cytes PAS staining as a screening test for nuclear inclusions of surfactant-specific apoprotein. Cancer. 1982 50 946-948. 

The respiratory distress syndrome (RDS) of a premature infant such as Colleen Lakker is, in part, related to a deficiency in the synthesis of a substance known as lung surfactant. The major constituents of surfactant are dipalmitoylphosphatidyl-choline, phosphatidylglycerol, apoproteins (surfactant proteins Sp-A,B,C), and cholesterol. 

A common structural feature of most apolipoproteins is the presence of amphipathic helical structures, which are thought to be responsible for binding apoproteins to lipids of the surface monolayer [60]. Each a-helix contains a hydrophilic and a hydrophobic face the hydrophilic face is exposed to water, whereas the hydrophobic face associates with lipids of the monolayer. Such amphiphilic structure enables apolipoproteins to function as natural surfactants... 

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