Nectins

Nectins are a family of transmembrane proteins that play a crucial role in cell-cell adhesion. They belong to the immunoglobulin superfamily and are characterized by their extracellular immunoglobulin-like domains and intracellular tail that interacts with other proteins. Nectins are essential for the formation and maintenance of adherens junctions, which are vital for tissue integrity and organization.

There are four main types of nectins in mammals: nectin-1, nectin-2, nectin-3, and nectin-4. These nectins can form homodimers (binding to themselves) or heterodimers (binding to other nectin types) to mediate cell adhesion. Their interactions are calcium-dependent, although less so than classical cadherins.

Nectins are involved in a variety of biological processes beyond simple adhesion. They play roles in cell polarization, migration, proliferation, and differentiation. They are also implicated in developmental processes, such as embryonic development and tissue regeneration. Furthermore, nectins have been linked to disease states, including cancer, where their dysregulation can contribute to tumor progression and metastasis. Research into nectins continues to uncover their complex roles in cellular communication and tissue homeostasis.