SFTPB

Surfactant protein B
File:Surfactant protein B structure.png Structure of Surfactant Protein B
Identifiers
Symbol	?
NCBI gene	6439
HGNC	10799
OMIM	178640
RefSeq	NM_000542
UniProt	P07988
Search for Structures Swiss-model Domains InterPro

Surfactant protein B (SFTPB) is a critical protein involved in the function of pulmonary surfactant, a complex mixture of lipids and proteins that reduces surface tension in the alveoli of the lungs, preventing alveolar collapse and facilitating gas exchange. SFTPB is encoded by the SFTPB gene located on chromosome 2 in humans.

Structure

SFTPB is a hydrophobic protein that is essential for the proper functioning of lung surfactant. It is synthesized as a large precursor protein, proSP-B, which is processed into the mature, active form. The mature protein is approximately 8 kDa in size and consists of 79 amino acids. It contains several amphipathic helices that allow it to interact with the lipid components of surfactant, enhancing its ability to reduce surface tension.

Function

SFTPB plays a crucial role in the formation and stabilization of the surfactant film that lines the alveoli. It enhances the spreading and adsorption of phospholipids at the air-liquid interface, which is vital for reducing surface tension and preventing alveolar collapse during expiration. SFTPB also contributes to the host defense mechanisms of the lung by facilitating the clearance of pathogens and debris.

Genetics

The SFTPB gene is located on chromosome 2p11.2. Mutations in this gene can lead to surfactant metabolism dysfunction, which is associated with respiratory distress syndrome (RDS) in newborns and interstitial lung disease in adults. The most common mutation associated with severe neonatal RDS is a frameshift mutation that results in a truncated, non-functional protein.

Clinical Significance

Deficiency or dysfunction of SFTPB is linked to several pulmonary conditions. In neonates, a lack of functional SFTPB can cause respiratory distress syndrome, a life-threatening condition that requires immediate medical intervention, often with exogenous surfactant therapy. In adults, mutations in the SFTPB gene can contribute to chronic lung diseases such as interstitial lung disease and pulmonary fibrosis.

Research and Therapeutics

Research into SFTPB has led to the development of synthetic and animal-derived surfactant replacement therapies, which are used to treat premature infants with RDS. Ongoing studies are exploring gene therapy and other novel approaches to address SFTPB deficiencies.

Also see

• Surfactant protein A
• Surfactant protein C
• Respiratory distress syndrome
• Pulmonary surfactant
• Interstitial lung disease