tenascin-X; TN-X; hexabrachion-like protein (TNXB HXBL TNX TNXB1 TNXB2 XB)

Function

• appears to mediate interactions between cells & the extracellular matrix
• substrate-adhesion molecule that appears to inhibit cell migration
• accelerates collagen fibril formation
• interacts with collagens
  • collagen type 1
  • collagen type 3
  • collagen type 5
• interacts with tropoelastin

Structure

• homotrimer
• belongs to the tenascin family
• contains 19 EGF-like domains
• contains 1 fibrinogen C-terminal domain
• contains 32 fibronectin F3 modules
  • interacts with collagens & tropoelastin via its 29th fibronectin F3 module

Compartment

• secreted, extracellular space, extracellular matrix

Alternative splicing

named isoforms=3; XB; XB-short

Expression

• highly expressed in fetal adrenal, in fetal testis, fetal smooth muslce, striated muscle & cardiac muscle
• isoform XB-short is only expressed in the adrenal gland
• expression levels are lower in adults than in children

Pathology

• may play a role in supporting growth of epithelial tumors
• association with congenital adrenal hyperplasia
• defects in TNXB are the cause of tenascin-X deficiency

Genetics

• there are two genes for tenascin-X: TNXA & TNXB
• TNXA is a partial gene which can sometimes recombine with TNXB

More general terms

• tenascin family

Database

• UniProt: http://www.uniprot.org/uniprot/P22105.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=7148
• OMIM: https://mirror.omim.org/entry/130020
• OMIM: https://mirror.omim.org/entry/600985
• OMIM: https://mirror.omim.org/entry/606408