Binding of Annexins to Lung Lamellar Bodies and the PMA-Stimulated Secretion of Annexin V from Alveolar Type II Cells

• Published in: Journal of biochemistry (Tokyo) Vol. 130; no. 3; pp. 449 - 455
• Main Authors: Sohma, Hitoshi, Ohkawa, Hiroko, Akino, Toyoaki, Kuroki, Yoshio
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-09-2001
• Subjects: alveolar type II cell; Animals; annexin; Annexin A5 - agonists; Annexin A5 - metabolism; Annexins - chemistry; Annexins - isolation & purification; Annexins - metabolism; Bronchoalveolar Lavage Fluid - chemistry; Bronchoalveolar Lavage Fluid - cytology; Calcium - metabolism; Carrier Proteins - chemistry; Carrier Proteins - isolation & purification; Carrier Proteins - metabolism; Cattle; Cytoplasmic Granules - metabolism; Cytoplasmic Granules - ultrastructure; lamellar body; Male; Organelles - metabolism; Organelles - ultrastructure; Phorbol Esters - metabolism; Phorbol Esters - pharmacology; Proteolipids - metabolism; Pulmonary Alveoli - cytology; Pulmonary Alveoli - metabolism; pulmonary surfactant; Pulmonary Surfactant-Associated Protein A; Pulmonary Surfactant-Associated Proteins; Pulmonary Surfactants - metabolism; Rabbits; Rats; Rats, Sprague-Dawley; Recombinant Proteins - metabolism; secretion; Sequence Analysis, Protein
• DOI: 10.1093/oxfordjournals.jbchem.a003005
• ISSN: 0021-924X

To identify lung lamellar body (LB)-binding proteins, the fractions binding to LB-Se-pharose 4B in a Ca2+-dependent manner from the lung soluble fractions were analyzed with Mono Q column. Four annexins (annexins III, IV, V, and VIII) were identified by partial amino acid sequence analyses as the LB-binding proteins in the lung soluble fractions. A control experiment using phospholipid (phosphatidylserine/phosphatidylg-lycerol/phosphtidylcholine) liposome-Sepharose 4B revealed that annexins III, IV and V were the Ca2+-dependent proteins binding to the column in the lung soluble fractions, while annexin Vlll was not detected. Thus, annexin VJJJ might preferentially bind to LB. On the other hand, the only Ca2+-dependent LB-binding protein identified in the bron-choalveolar lavage fluids was annexin V. It was further demonstrated that annexin V was secreted by isolated alveolar type II cells from rats and that the secretion was stimulated by the addition of phorbol ester (PMA), a potent stimulator of surfactant secretion. The PMA-dependent stimulation of annexin V was attenuated by preincubation with surfactant protein-A (SP-A), a potent inhibitor of surfactant secretion. As LB is thought to be an intracellular store of pulmonary surfactant, which is secreted by alveolar type II cells, annexin V is likely to be secreted together with the lamellar body.