Type XXIII Collagen, a New Transmembrane Collagen Identified in Metastatic Tumor Cells

Jacqueline Banyard,Lere Bao,Bruce R Zetter

doi:10.1074/jbc.m210616200

Jacqueline Banyard, Lere Bao + Show 1 more

Open Access

https://doi.org/10.1074/jbc.m210616200

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Abstract

We have identified a transmembrane collagen, collagen XXIII, in rat prostate carcinoma cells. Differential display of mRNA expression in prostate carcinoma sublines with varying metastatic potential revealed overexpression of this transcript in the metastatic AT6.1 subline. cDNA cloning identified a 2733-bp transcript from AT6.1 RNA, encoding a protein of 532 amino acids, together with a 3067-bp human homologue, resulting in a 540-amino acid protein. Collagen XXIII is predicted to be a type II membrane protein consisting of an amino-terminal cytoplasmic domain, a transmembrane region, and three collagenous domains flanked by short noncollagenous domains. Collagen XXIII is a new member of the transmembrane collagen family, showing structural homology with the transmembrane collagens XIII and XXV. We present evidence that collagen XXIII is expressed as a approximately 75-kDa protein at the cell surface and that it can be cleaved by furin protease activity. Cleavage results in a approximately 60-kDa soluble protein that forms a multimeric complex and exhibits a low affinity interaction with heparin.

Highlights

The extracellular environment consists of a complex mix of matrix macromolecules together with sequestered growth factors
Considering the high identity between human, rat, and mouse cDNAs, and the longer 5Ј sequences identified in human and mouse, we note the possibility of additional transcriptional start sites in the rat collagen XXIII gene, in addition to the site we have identified by Inverse RACE
Collagen XXIII consists of a long amino-terminal noncollagenous (NC) domain, NC-1, containing a short cytoplasmic region and a putative membrane spanning domain, followed by three collagenous (COL1–COL3) domains in the extracellular region of the protein that are interrupted by short noncollagenous domains (NC2–NC4), as shown in the schematic (Fig. 3)

Summary

Introduction

The extracellular environment consists of a complex mix of matrix macromolecules together with sequestered growth factors. We have identified a transmembrane collagen, collagen XXIII, in rat prostate carcinoma cells. We report here the cloning of a new transmembrane collagen overexpressed in rat prostate adenocarcinoma cells and characterize its cellular localization, its cleavage, and the properties of its soluble ectodomain.

Results

Conclusion