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Examining O‐xylosyltransferase in Drosophila
Author(s) -
Palus Brooke,
Selva Erica
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.558.2
Subject(s) - microbiology and biotechnology , endoplasmic reticulum , golgi apparatus , extracellular , extracellular matrix , biology , homeostasis , transmembrane protein , biochemistry , receptor
O‐xylosyltransferase (Oxt) is a transmembrane glycosyltransferase that initiates the first step in heperan and chrondroitin sulfate (HS and CS) proteoglycan biosynthesis. HSPGs and CSPGs are abundant in the extracellular environment of many tissues, such as articular cartilage in humans. In this tissue, HSPGs and CSPGs are essential regulation of signaling pathways that maintain tissue homeostasis. If homeostasis is not preserved, joint tissue will degrade and osteoarthritis (OA) can occur. Elevated levels of circulating Oxt have been detected in human OA patients suggesting shed Oxt may have an extracellular function. Little is known about Oxt behavior or function once it is released from the plasma membrane. Cell culture experiments have shown that Oxt, normally located in the Golgi and the endoplasmic reticulum (ER), can be shed by proteolysis activity and move into the media. It is likely that the same result will be observed in vivo. The overall aim of this project is to determine if Oxt released from expressing cells in vivo and what, if any, function extracellular Oxt has in organismal development. The data collected thus far shows localization of Oxt to the Golgi and the ER where it could have an active role in HSPG and CSPG biosynthesis. Movement of Oxt from expressing cells to non‐expressing cells is observed in the imaginal wing disc of Drosophila larva. Extracellular staining shows that Oxt is found predominantly on the apical surface and can be detected in the peripodial space suggesting it is released from expressing cells. Western analysis of Drosophila hemolymph indicated Oxt is released into hemolymph, as observed in humans. The results suggest that cleaved Oxt is found in the hemolymph of Drosophila and future studies will explore the potential function of shed Oxt.