|ZFIN ID: ZDB-PUB-071016-5|
OS-9 regulates the transit and polyubiquitination of TRPV4 in the endoplasmic reticulum
Wang, Y., Fu, X., Gaiser, S., Köttgen, M., Kramer-Zucker, A., Walz, G., and Wegierski, T.
|Source:||The Journal of biological chemistry 282(50): 36561-36570 (Journal)|
|Registered Authors:||Kramer-Zucker, Albrecht, Wegierski, Tomasz|
|PubMed:||17932042 Full text @ J. Biol. Chem.|
Wang, Y., Fu, X., Gaiser, S., Köttgen, M., Kramer-Zucker, A., Walz, G., and Wegierski, T. (2007) OS-9 regulates the transit and polyubiquitination of TRPV4 in the endoplasmic reticulum. The Journal of biological chemistry. 282(50):36561-36570.
ABSTRACTTransient Receptor Potential (TRP) proteins constitute a family of cation-permeable channels that are formed by homo- or heteromeric assembly of four subunits. Despite recent progress in the identification of protein domains required for the formation of tetramers, the mechanisms governing TRP channel assembly, and biogenesis in general, remain largely elusive. Especially little is known about the involvement of regulatory proteins in these processes. Here we report, that OS-9, a ubiquitously expressed endoplasmic reticulum (ER)-associated protein, interacts with the cytosolic amino-terminal tail of TRPV4. Using a combination of co-expression and knock-down approaches we have found that OS-9 impedes the release of TRPV4 from the ER and reduces its amount at the plasma membrane. Consistent with these in vitro findings, OS-9 protected zebrafish embryos against the detrimental effects of TRPV4 expression in vivo. A detailed analysis of the underlying mechanisms revealed that OS-9 preferably binds TRPV4 monomers and other ER-localized, immature variants of TRPV4, and attenuates their polyubiquitination. Thus, OS-9 regulates the secretory transport of TRPV4 and appears to protect TRPV4 subunits from the precocious ubiquitination and ER-associated degradation. Our data suggest that OS-9 functions as an auxiliary protein for TRPV4 maturation.
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