MAPK signaling to the early secretory pathway revealed by kinase/phosphatase functional screening

• Published in: The Journal of cell biology Vol. 189; no. 6; pp. 997 - 1011
• Main Authors: Farhan, Hesso, Wendeler, Markus W, Mitrovic, Sandra, Fava, Eugenio, Silberberg, Yael, Sharan, Roded, Zerial, Marino, Hauri, Hans-Peter
• Format: Journal Article
• Language: English
• Published: United States The Rockefeller University Press 14.06.2010; Rockefeller University Press
• Subjects: Animals; Biochemistry; biogenesis; Budding; Cells; coat proteins; Complementary DNA; COP-Coated Vesicles - metabolism; Databases, Factual; endoplasmic reticulum; Endoplasmic Reticulum - metabolism; Enzymes; Epithelial cells; exports; Fluorescence Recovery After Photobleaching; Gene expression regulation; Golgi apparatus; Golgi Apparatus - metabolism; HeLa Cells; Humans; Kinases; Mannose-Binding Lectins - genetics; Mannose-Binding Lectins - metabolism; MAP Kinase Signaling System - physiology; Membrane Proteins - genetics; Membrane Proteins - metabolism; mitogen-activated protein kinase; Mitogen-Activated Protein Kinases - genetics; Mitogen-Activated Protein Kinases - metabolism; Phosphatases; Phosphoric Monoester Hydrolases - metabolism; Phosphorylation; Phosphotransferases - metabolism; Proteins; Ribonucleic acid; RNA; RNA Interference; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Secretory pathway; Secretory Pathway - physiology; Small interfering RNA; Vesicular Transport Proteins - genetics; Vesicular Transport Proteins - metabolism
• ISSN: 0021-9525; 1540-8140; 1540-8140
• DOI: 10.1083/jcb.200912082

To what extent the secretory pathway is regulated by cellular signaling is unknown. In this study, we used RNA interference to explore the function of human kinases and phosphatases in controlling the organization of and trafficking within the secretory pathway. We identified 122 kinases/phosphatases that affect endoplasmic reticulum (ER) export, ER exit sites (ERESs), and/or the Golgi apparatus. Numerous kinases/phosphatases regulate the number of ERESs and ER to Golgi protein trafficking. Among the pathways identified, the Raf-MEK (MAPK/ERK [extracellular signal-regulated kinase] kinase)-ERK cascade, including its regulatory proteins CNK1 (connector enhancer of the kinase suppressor of Ras-1) and neurofibromin, controls the number of ERESs via ERK2, which targets Sec16, a key regulator of ERESs and COPII (coat protein II) vesicle biogenesis. Our analysis reveals an unanticipated complexity of kinase/phosphatase-mediated regulation of the secretory pathway, uncovering a link between growth factor signaling and ER export.