Nectin

Nectins and Nectin-like molecules (Necl) are families of cellular adhesion molecules involved in Ca²⁺-independent cellular adhesion.

Nectins are ubiquitously expressed and have adhesive roles in a wide range of tissues such as the adherens junction of epithelia or the chemical synapse of the neuronal tissue.

Diversity

So far four nectins have been identified in humans, namely nectin-1, nectin-2, nectin-3 and nectin-4. These four family members have also been found in most other well studies mammals. Also, five Necls have been identified, these are: Necl-1, Necl-2, Necl-3, Necl-4 and Necl-5.

Structure

All nectins and all Necls share the same overall structure defined by three extra cellular immunoglobulin domains, a single transmembrane helix and an intracellular domain. For all nectins the intracellular domain can bind a scaffold protein named afadin (the product of the MLLT4 gene).

All nectins and Necls can form homo-cis dimers, meaning a dimer of two alike molecules on the same cell membrane. Following the homo-dimer formation they can trans-interact in an either heterophilic or homophilic manner. The network of the nectin and Necl trans-interactions has been characterized. Recent structural reports reveal the physical and chemical determinants of homophilic interactions mediated by N-terminal IgV domains. In general, heterophilic interactions among nectins have higher affinity than their respective homophilic interactions.

Poliovirus receptor-related 2

Poliovirus receptor-related 2 (PVRL2), also known as nectin-2 and CD112 (formerly herpesvirus entry mediator B, HVEB), is a human plasma membrane glycoprotein.

Function

This gene encodes a single-pass type I membrane glycoprotein with two Ig-like C2-type domains and an Ig-like V-type domain. This protein is one of the plasma membrane components of adherens junctions. It also serves as an entry for certain mutant strains of herpes simplex virus and pseudorabies virus, and it is involved in cell to cell spreading of these viruses. Variations in this gene have been associated with differences in the severity of multiple sclerosis. Alternate transcriptional splice variants, encoding different isoforms, have been characterized.

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This article incorporates text from the United States National Library of Medicine, which is in the public domain.

Poliovirus receptor-related 1

Poliovirus receptor-related 1 (PVRL1), also known as nectin-1 and CD111 (formerly herpesvirus entry mediator C, HVEC) is a human protein of the immunoglobulin superfamily (IgSF), also considered a member of the nectins. It is a membrane protein with three extracellular immunoglobulin domains, a single transmembrane helix and a cytoplasmic tail. The protein can mediate Ca²⁺-independent cellular adhesion further characterizing it as IgSF cell adhesion molecule (IgSF CAM).

Function

PVRL1 is adhesion molecule found in a wide range of tissues where is localizes in various junctions such as the adherens junction of epithelial tissue or the chemical synapse of neurons. The cytoplasmic tail of PVRL1 can bind the protein afadin which is a scaffolding protein that binds actin.

In the chemical synapse PVRL1 interacts with PVRL3 (nectin-3) and both proteins can be found in neuronal tissue already in early stages of brain development as well as in aging brains. Inerestingly the two proteins have been found to localize asymmetrically along the chemical synapse, with PVRL1 primarily on the axonal side and PVRL3 on the dendritic side.