title: Identification of ROCK1 kinase as a critical regulator of Beclin1-mediated autophagy during metabolic stress.
abstract: The Ser/Thr Rho kinase 1 (ROCK1) is known to have major roles in a wide range of cellular activities, including those involved in tumour metastasis and apoptosis. Here we identify an indispensable function of ROCK1 in metabolic stress-induced autophagy. Applying a proteomics approach, we characterize Beclin1, a proximal component of the phosphoinositide 3-kinase class III lipid-kinase complex that induces autophagy, as an interacting partner of ROCK1. Upon nutrient deprivation, activated ROCK1 promotes autophagy by binding and phosphorylating Beclin1 at Thr119. This results in the specific dissociation of the Beclin1-Bcl-2 complex without affecting the Beclin1-UVRAG interaction. Conversely, inhibition of ROCK1 activity increases Beclin1-Bcl-2 association, thus reducing nutritional stress-mediated autophagy. Genetic knockout of ROCK1 function in mice also leads to impaired autophagy as evidenced by reduced autophagosome formation. These results show that ROCK1 acts as a prominent upstream regulator of Beclin1-mediated autophagy and maintains a homeostatic balance between apoptosis and autophagy.
authors.affiliation: Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Aditi U
authors.initials: AU
authors.lastname: Gurkar
authors.forename: Kiki
authors.initials: K
authors.lastname: Chu
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Raj
authors.forename: Richard
authors.initials: R
authors.lastname: Bouley
authors.forename: Seung-Hwan
authors.initials: SH
authors.lastname: Lee
authors.forename: Young-Bum
authors.initials: YB
authors.lastname: Kim
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Dunn
authors.forename: Anna
authors.initials: A
authors.lastname: Mandinova
authors.forename: Sam W
authors.initials: SW
authors.lastname: Lee
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000235:genetics* / Q000378:metabolism; D001343:Autophagy / Q000235:genetics*; D000071186:Beclin-1; D002450:Cell Communication; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D010588:Phagosomes / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; D008565:Membrane Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins; C408122:UVRAG protein, human; C515851:ROCK1 protein, human; D054460:rho-Associated Kinases