title: ER trapping reveals Golgi enzymes continually revisit the ER through a recycling pathway that controls Golgi organization.
abstract: Whether Golgi enzymes remain localized within the Golgi or constitutively cycle through the endoplasmic reticulum (ER) is unclear, yet is important for understanding Golgi dependence on the ER. Here, we demonstrate that the previously reported inefficient ER trapping of Golgi enzymes in a rapamycin-based assay results from an artifact involving an endogenous ER-localized 13-kD FK506 binding protein (FKBP13) competing with the FKBP12-tagged Golgi enzyme for binding to an FKBP-rapamycin binding domain (FRB)-tagged ER trap. When we express an FKBP12-tagged ER trap and FRB-tagged Golgi enzymes, conditions precluding such competition, the Golgi enzymes completely redistribute to the ER upon rapamycin treatment. A photoactivatable FRB-Golgi enzyme, highlighted only in the Golgi, likewise redistributes to the ER. These data establish Golgi enzymes constitutively cycle through the ER. Using our trapping scheme, we identify roles of rab6a and calcium-independent phospholipase A2 (iPLA2) in Golgi enzyme recycling, and show that retrograde transport of Golgi membrane underlies Golgi dispersal during microtubule depolymerization and mitosis.
authors.affiliation: The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Prabuddha
authors.initials: P
authors.lastname: Sengupta
authors.affiliation: The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Prasanna
authors.initials: P
authors.lastname: Satpute-Krishnan
authors.affiliation: The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Arnold Y
authors.initials: AY
authors.lastname: Seo
authors.affiliation: The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Dylan T
authors.initials: DT
authors.lastname: Burnette
authors.affiliation: The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
authors.forename: George H
authors.initials: GH
authors.lastname: Patterson
authors.affiliation: The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892 lippincj@mail.nih.gov.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lippincott-Schwartz
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006056:Golgi Apparatus / Q000201:enzymology*; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D054512:Phospholipases A2, Calcium-Independent / Q000502:physiology; D020123:Sirolimus / Q000494:pharmacology; D022061:Tacrolimus Binding Protein 1A / Q000378:metabolism; D022021:Tacrolimus Binding Proteins / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000502:physiology
chemical_list: C094135:Rab6 protein; C070133:FKBP-13; D054512:Phospholipases A2, Calcium-Independent; D020691:rab GTP-Binding Proteins; D022061:Tacrolimus Binding Protein 1A; D022021:Tacrolimus Binding Proteins; D020123:Sirolimus
keywords: ER; Golgi; mitosis; rapamycin; recycling