Palmitoylation and processing of the lipopeptide surfactant protein C.
Pulmonary surfactant, a mixture of lipids and proteins, reduces the surface tension at the air-water interface of the lung alveoli by forming a surface active film. This way, it prevents alveoli from collapsing and facilitates the work of breathing. Surfactant protein C (SP-C) plays an important role in this surfactant function. SP-C is expressed as a proprotein (proSP-C), which becomes posttranslationally modified with palmitate and undergoes several rounds of proteolytical cleavage. This results in the formation of mature SP-C, which is stored in the lamellar bodies (LB) and finally secreted into the alveolar space. Recently, new insights into the sorting, processing and palmitoylation of proSP-C have been obtained by mutagenesis studies. Moreover, reports on the association of development of lung disease with SP-C deficiency have led to new insights into the importance of SP-C for proper surfactant homeostasis. In addition, new information has become available on the role of the palmitoyl chains of SP-C in surface activity. This review summarizes these recent developments in the processing and function of SP-C, with particular emphasis on the signals for and role of palmitoylation of SP-C.
ten Brinke
Anja
A
Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands.
van Golde
Lambert M G
LM
Batenburg
Joseph J
JJ
D000595:Amino Acid Sequence; D000818:Animals; D006706:Homeostasis; D006801:Humans; D008168:Lung / Q000502:physiology; D008171:Lung Diseases / Q000503:physiopathology; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D011510:Proteolipids / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D037721:Pulmonary Surfactant-Associated Protein C; D011663:Pulmonary Surfactants / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
D010455:Peptides; D011510:Proteolipids; D037721:Pulmonary Surfactant-Associated Protein C; D011663:Pulmonary Surfactants; C489679:SFTPC protein, human