LTBP1

LTBP1, or latent transforming growth factor beta-binding protein 1, is an extracellular matrix glycoprotein that regulates the storage and activation of transforming growth factor beta (TGF-β). It is encoded by the LTBP1 gene in humans and is the best-characterized member of the latent TGF-β binding protein family, which also includes LTBP2, LTBP3, and LTBP4.

LTBP-1 is secreted into the extracellular matrix where it binds to the large latent TGF-β complex and anchors it to ECM components, particularly microfibrils formed by fibrillin-1. This tethering controls the local reservoir of latent TGF-β and modulates its bioavailability and signaling potential.

LTBP-1 contributes to extracellular matrix organization by interacting with other matrix proteins and supports the assembly and stability of microfibrillar structures.

Activation: the latent complex bound by LTBP-1 can be activated by proteolytic enzymes or by cell-surface integrins, releasing active TGF-β to engage its receptors and trigger signaling pathways involved in cell migration, proliferation, and differentiation.

Expression and role: LTBP1 is broadly expressed in many tissues, with expression patterns that change during development, wound healing, and tissue remodeling. It is studied for its role in regulating TGF-β signaling in development and disease.

Clinical relevance: Alterations in LTBP1 expression or function have been investigated in models of fibrosis and connective tissue biology, reflecting its contribution to TGF-β–mediated processes.

See also: latent TGF-β complex, TGF-β signaling, LTBP family.