SEMA7A

SEMA7A‏‎ (Semaphorin-7A), also known as CD108 (Cluster of Differentiation 108), is a protein that in humans is encoded by the SEMA7A gene. It is a member of the semaphorin family and plays a significant role in immune response, neuronal development, and bone remodeling.

Function[edit | edit source]

SEMA7A is a glycosylphosphatidylinositol (GPI)-linked member of the semaphorin family. Semaphorins are a large family of conserved secreted and membrane-associated proteins which possess a semaphorin (Sema) domain and a PSI domain (found in plexins, semaphorins and integrins) in the N-terminal extracellular portion. Based on sequence and structural similarities, semaphorins are put into eight classes: invertebrates contain classes 1 and 2, viruses have class V, and vertebrates contain classes 3-7. Semaphorins serve as axon guidance ligands via multimeric receptor complexes, some (if not all) containing plexin proteins.

SEMA7A functions as an immune modulator and upregulates T cell responses. It also stimulates monocytes and macrophages through a receptor complex of integrin beta1 and plexin C1. In the nervous system, SEMA7A promotes axon outgrowth and is a potent inhibitor of angiogenesis. In bone tissue, it is involved in osteoclast differentiation and function, contributing to bone remodeling.

Clinical Significance[edit | edit source]

Alterations in SEMA7A expression have been associated with several diseases. It has been implicated in the pathogenesis of multiple sclerosis due to its role in immune response. In cancer, SEMA7A can promote tumor growth and metastasis. It is also involved in the progression of pulmonary fibrosis, and its overexpression can lead to increased fibroblast proliferation and migration.