PT  - JOURNAL ARTICLE
AU  - Gaetan G. Herbomel
AU  - Raul E. Rojas
AU  - Duy T. Tran
AU  - Monica Ajinkya
AU  - Lauren Beck
AU  - Lawrence A. Tabak
TI  - Growth Factors do not regulate Golgi Complex-to-ER relocation of GalNAc-Ts in HeLa cells
AID  - 10.1101/071225
DP  - 2016 Jan 01
TA  - bioRxiv
PG  - 071225
4099  - http://biorxiv.org/content/early/2016/08/23/071225.short
4100  - http://biorxiv.org/content/early/2016/08/23/071225.full
AB  - Mucin-type O-glycosylation is initiated by the UDP-GalNAc polypeptide:N-acetylgalactosaminyltransferase (GalNAc-T) family of enzymes. Their activity results in the GalNAc α1-O-Thr/Ser structure, termed the Tn antigen, which is further decorated with additional sugars. In neoplastic cells, the Tn antigen is often overexpressed. Because O-glycosylation is controlled by the activity of GalNAc-Ts, their regulation is of great interest. Previous reports suggest that growth factors, EGF or PDGF, induce Golgi complex-to-endoplasmic reticulum (ER) relocation of both GalNAc-Ts and Tn antigen in HeLa cells, offering a mechanism for Tn antigen overexpression termed “GALA”. However, we were unable to reproduce these findings. Upon treatment of HeLa cells with either EGF or PDGF we observed no change in the co-localization of endogenous GalNAc-T1, GalNAc-T2 or Tn antigen with the Golgi complex marker TGN46. There was also no enhancement of localization with the ER marker calnexin. We conclude that growth factors do not cause redistribution of GalNAc-Ts from the Golgi complex to the ER in HeLa cells.GalNAc-TUDP-GalNAc polypeptide:N acetylgalactosaminyltransferaseGalNAcN-acetylgalactosamineEREndoplasmic reticulumEGFEpidermal growth factorPDGFPlatelet-derived growth factorMAPKMitogen-activated protein kinaseNANumerical aperatureAUAiry unitMCCManders’ correlation coefficient