Protein transport and targeting within the endomembrane system of plants

1991 ◽  
pp. 199-237 ◽  
Author(s):  
A. B. Bennett ◽  
K. W. Osteryoung
Keyword(s):  
Protein Transport ◽  
Endomembrane System

Protein transport within the plant cell endomembrane system: an update

1998 ◽  
Vol 1 (6) ◽  
pp. 463-469 ◽  
Author(s):  
Ken Matsuoka ◽  
Sebastian Y. Bednarek
Keyword(s):  
Plant Cell ◽  
Protein Transport ◽  
Endomembrane System

scholarly journals A new type of ERGIC-ERES membrane contact mediated by TMED9 and SEC12 is required for autophagosome biogenesis

2021 ◽  
Author(s):  
Shulin Li ◽  
Rui Yan ◽  
Jialu Xu ◽  
Shiqun Zhao ◽  
Xinyu Ma ◽  
...  
Keyword(s):  
Short Distance ◽  
Protein Transport ◽  
Secretory Protein ◽  
Endomembrane System ◽  
Exit Site ◽  
Copii Vesicle ◽  
Golgi System ◽  
New Type ◽  
Membrane Contact ◽  
Intermediate Compartment

Under stress, the endomembrane system undergoes reorganization to support autophagosome biogenesis, which is a central step in autophagy. How the endomembrane system remodels has been poorly understood. Here we identify a new type of membrane contact formed between the ER-Golgi intermediate compartment (ERGIC) and the ER-exit site (ERES) in the ER-Golgi system, which is essential for promoting autophagosome biogenesis induced by different stress stimuli. The ERGIC-ERES contact is established by the interaction between TMED9 and SEC12 which generates a short distance opposition (as close as 2-5 nm) between the two compartments. The tight membrane contact allows the ERES-located SEC12 to transactivate COPII assembly on the ERGIC. In addition, a portion of SEC12 also relocates to the ERGIC. Through both mechanisms, the ERGIC-ERES contact promotes formation of the ERGIC-derived COPII vesicle, a membrane precursor of the autophagosome. The ERGIC-ERES contact is physically and functionally different from the TFG-mediated ERGIC-ERES adjunction involved in secretory protein transport, and therefore defines a unique endomembrane structure generated upon stress conditions for autophagic membrane formation.

scholarly journals The Golgi apparatus regulates cGMP-dependent protein kinase I compartmentation and proteolysis

2015 ◽  
Vol 308 (11) ◽  
pp. C944-C958 ◽  
Author(s):  
Shin Kato ◽  
Jingsi Chen ◽  
Katherine H. Cornog ◽  
Huili Zhang ◽  
Jesse D. Roberts
Keyword(s):  
Protein Kinase ◽  
Golgi Apparatus ◽  
Protein Transport ◽  
Endomembrane System ◽  
Dependent Protein Kinase ◽  
Trans Golgi Network ◽  
Cgmp Dependent Protein Kinase ◽  
Cgmp Signaling ◽  
Dependent Protein ◽  
Golgi Network

cGMP-dependent protein kinase I (PKGI) is an important effector of cGMP signaling that regulates vascular smooth muscle cell (SMC) phenotype and proliferation. PKGI has been detected in the perinuclear region of cells, and recent data indicate that proprotein convertases (PCs) typically resident in the Golgi apparatus (GA) can stimulate PKGI proteolysis and generate a kinase fragment that localizes to the nucleus and regulates gene expression. However, the role of the endomembrane system in PKGI compartmentation and processing is unknown. Here, we demonstrate that PKGI colocalizes with endoplasmic reticulum (ER), ER-Golgi intermediate compartment, GA cisterna, and trans-Golgi network proteins in pulmonary artery SMC and cell lines. Moreover, PKGI localizes with furin, a trans-Golgi network-resident PC known to cleave PKGI. ER protein transport influences PKGI localization because overexpression of a constitutively inactive Sar1 transgene caused PKGI retention in the ER. Additionally, PKGI appears to reside within the GA because PKGI immunoreactivity was determined to be resistant to cytosolic proteinase K treatment in live cells. The GA appears to play a role in PKGI proteolysis because overexpression of inositol 1,4,5-trisphosphate receptor-associated cGMP kinase substrate, not only tethered heterologous PKGI-β to the ER and decreased its localization to the GA, but also diminished PKGI proteolysis and nuclear translocation. Also, inhibiting intra-GA protein transport with monensin was observed to decrease PKGI cleavage. These studies detail a role for the endomembrane system in regulating PKGI compartmentation and proteolysis. Moreover, they support the investigation of mechanisms regulating PKGI-dependent nuclear cGMP signaling in the pulmonary vasculature with Golgi dysfunction.

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