PUBLICATION
A Mammalian Homolog of the Zebrafish Transmembrane Protein 2 (TMEM2) Is the Long-sought-after Cell Surface Hyaluronidase
- Authors
- Yamamoto, H., Tobisawa, Y., Inubushi, T., Irie, F., Oyama, C., Yamaguchi, Y.
- ID
- ZDB-PUB-170302-8
- Date
- 2017
- Source
- The Journal of biological chemistry 292(18): 7304-7313 (Journal)
- Registered Authors
- Keywords
- CEMIP/KIAA1199, TMEM2, cell surface, glycosaminoglycan, hyaluronan, hyaluronidase, membrane function
- MeSH Terms
-
- Animals
- Calcium/metabolism
- Cell Line
- Cell Membrane/enzymology*
- Cell Membrane/genetics
- Gene Expression Regulation, Enzymologic/physiology*
- Humans
- Hyaluronic Acid/genetics
- Hyaluronic Acid/metabolism*
- Hyaluronoglucosaminidase/biosynthesis*
- Hyaluronoglucosaminidase/genetics
- Hydrogen-Ion Concentration
- Membrane Proteins/biosynthesis*
- Membrane Proteins/genetics
- Mice
- PubMed
- 28246172 Full text @ J. Biol. Chem.
Citation
Yamamoto, H., Tobisawa, Y., Inubushi, T., Irie, F., Oyama, C., Yamaguchi, Y. (2017) A Mammalian Homolog of the Zebrafish Transmembrane Protein 2 (TMEM2) Is the Long-sought-after Cell Surface Hyaluronidase. The Journal of biological chemistry. 292(18):7304-7313.
Abstract
Hyaluronan (HA) is an extremely large polysaccharide (glycosaminoglycan) involved in many cellular functions. HA catabolism is thought to involve the initial cleavage of extracellular high-molecular-weight (HMW) HA into intermediate-size HA by an extracellular or cell-surface hyaluronidase, internalization of intermediate-size HA, and complete degradation into monosaccharides in lysosomes. Despite considerable research, the identity of the hyaluronidase responsible for the initial HA cleavage in the extracellular space remains elusive. HYAL1 and HYAL2 have properties more consistent with lysosomal hyaluronidases, whereas CEMIP/KIAA1199, a recently identified HA-binding molecule that has HA-degrading activity, requires the participation of the clathrin-coated pit pathway of live cells for HA degradation. Here we show that transmembrane protein 2 (TMEM2), a mammalian homolog of a protein playing a role in zebrafish endocardial cushion development, is a cell-surface hyaluronidase. Live immunostaining and surface biotinylation assays confirmed that mouse TMEM2 is expressed on the cell surface in a type II transmembrane topology. TMEM2 degraded HMW-HA into ∼5-kDa fragments but did not cleave chondroitin sulfate or dermatan sulfate, indicating its specificity to HA. The hyaluronidase activity of TMEM2 was Ca2+-dependent; the enzyme's pH optimum is around 6-7, and unlike CEMIP/KIAA1199, TMEM2 does not require the participation of live cells for its hyaluronidase activity. Moreover, TMEM2-expressing cells could eliminate HA immobilized on a glass surface in a contact-dependent manner. Together, these data suggest that TMEM2 is the long-sought-after hyaluronidase that cleaves extracellular HMW-HA into intermediate-size fragments before internalization and degradation in the lysosome.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping