Kinases regulating Golgi apparatus structure and function.

2005 ◽  
Vol 72 ◽  
pp. 15-30 ◽  
Author(s):  
Christian Preisinger ◽  
Francis A. Barr

Protein kinases control Golgi function in both mitotic and interphase cells. In mitosis, phosphorylation of structural proteins by Cdk1 (cyclin-dependent kinase 1)-cyclin B, Polo-like and mitogen-activated protein kinases underlie changes in Golgi reorganization during cell division. While in interphase, signalling pathways that are associated with the Golgi control secretory function through a variety of mechanisms. Some of these, notably those involving protein kinase D and Ste20 family kinases, are also relevant for the establishment and maintenance of cell polarization and migration.

2000 ◽  
Vol 89 (6) ◽  
pp. 2391-2400 ◽  
Author(s):  
Hiroyuki Kito ◽  
Emery L. Chen ◽  
Xiujie Wang ◽  
Masataka Ikeda ◽  
Nobuyoshi Azuma ◽  
...  

The aim of this study was to examine the role of mitogen-activated protein kinases (MAPKs) activation in bovine pulmonary arterial endothelial cells (EC) exposed to cyclic strain. EC were subjected to 10% average strain at 60 cycles/min. Cyclic strain induced activation of extracellular signal-regulated kinase (ERK; 1.5-fold), c-Jun NH2-terminal protein kinase (JNK; 1.9-fold), and p38 (1.5-fold) with a peak at 30 min. To investigate the functional role of the activated MAPKs, we analyzed cells after treatment with PD-98059, a specific ERK kinase inhibitor, or SB-203580, a catalytic inhibitor for p38, and after transient transfection with JNK(K-R), and MEKK(K-M) the respective catalytically inactive mutants of JNK1 and MAPK kinase kinase-1. Cyclic strain increased activator protein-1 (AP-1) binding activity, which was blocked by PD-98059 and SB-203580. Activity of AP-1-dependent luciferase reporter driven by 12- O-tetradecanoyl-phorbol-13-acetate-responsive element (TRE) was induced by cyclic strain, and this was attenuated by PD-98059, MEKK(K-M), JNK(K-R), and SB-203580. PD-98059 and SB-203850 did not inhibit cell alignment and migration induced by cyclic strain. MEKK(K-M) and JNK(K-R) transfection did not block cyclic strain-induced cell alignment. In conclusion, cyclic strain activates ERK, JNK, and p38, and their activation plays a role in transcriptional activation of AP-1/TRE but not in cell alignment and migration changes in bovine pulmonary arterial EC.


2008 ◽  
Vol 19 (4) ◽  
pp. 1739-1752 ◽  
Author(s):  
Lu Yu ◽  
Maosong Qi ◽  
Mark A. Sheff ◽  
Elaine A. Elion

Cell polarization in response to external cues is critical to many eukaryotic cells. During pheromone-induced mating in Saccharomyces cerevisiae, the mitogen-activated protein kinase (MAPK) Fus3 induces polarization of the actin cytoskeleton toward a landmark generated by the pheromone receptor. Here, we analyze the role of Fus3 activation and cell cycle arrest in mating morphogenesis. The MAPK scaffold Ste5 is initially recruited to the plasma membrane in random patches that polarize before shmoo emergence. Polarized localization of Ste5 is important for shmooing. In fus3 mutants, Ste5 is recruited to significantly more of the plasma membrane, whereas recruitment of Bni1 formin, Cdc24 guanine exchange factor, and Ste20 p21-activated protein kinase are inhibited. In contrast, polarized recruitment still occurs in a far1 mutant that is also defective in G1 arrest. Remarkably, loss of Cln2 or Cdc28 cyclin-dependent kinase restores polarized localization of Bni1, Ste5, and Ste20 to a fus3 mutant. These and other findings suggest Fus3 induces polarized growth in G1 phase cells by down-regulating Ste5 recruitment and by inhibiting Cln/Cdc28 kinase, which prevents basal recruitment of Ste5, Cdc42-mediated asymmetry, and mating morphogenesis.


2013 ◽  
Vol 394 (9) ◽  
pp. 1115-1132 ◽  
Author(s):  
Ugo Moens ◽  
Sergiy Kostenko

Abstract Mitogen-activated protein kinase (MAPK) pathways are important signal transduction pathways that control pivotal cellular processes including proliferation, differentiation, survival, apoptosis, gene regulation, and motility. MAPK pathways consist of a relay of consecutive phosphorylation events exerted by MAPK kinase kinases, MAPK kinases, and MAPKs. Conventional MAPKs are characterized by a conserved Thr-X-Tyr motif in the activation loop of the kinase domain, while atypical MAPKs lack this motif and do not seem to be organized into the classical three-tiered kinase cascade. One functional group of conventional and atypical MAPK substrates consists of protein kinases known as MAPK-activated protein kinases. Eleven mammalian MAPK-activated protein kinases have been identified, and they are divided into five subgroups: the ribosomal-S6-kinases RSK1-4, the MAPK-interacting kinases MNK1 and 2, the mitogen- and stress-activated kinases MSK1 and 2, the MAPK-activated protein kinases MK2 and 3, and the MAPK-activated protein kinase MK5 (also referred to as PRAK). MK5/PRAK is the only MAPK-activated protein kinase that is a substrate for both conventional and atypical MAPK, while all other MAPKAPKs are exclusively phosphorylated by conventional MAPKs. This review focuses on the structure, activation, substrates, functions, and possible implications of MK5/PRAK in malignant and nonmalignant diseases.


2005 ◽  
Vol 25 (14) ◽  
pp. 6090-6102 ◽  
Author(s):  
Sotiris N. Nikolopoulos ◽  
Pamela Blaikie ◽  
Toshiaki Yoshioka ◽  
Wenjun Guo ◽  
Claudia Puri ◽  
...  

ABSTRACT The α6β4 integrin—a laminin-5 receptor—mediates assembly of hemidesmosomes and recruitment of Shc and phosphoinositide 3-kinase through the unique cytoplasmic extension of β4. Mice carrying a targeted deletion of the signaling domain of β4 develop normally and do not display signs of skin fragility. The epidermis of these mice contains well-structured hemidesmosomes and adheres stably to the basement membrane. However, it is hypoplastic due to reduced proliferation of basal keratinocytes and undergoes wound repair at a reduced rate. Keratinocytes from β4 mutant mice undergo extensive spreading but fail to proliferate and migrate in response to epidermal growth factor (EGF) on laminin-5. EGF causes significant phosphorylation of extracellular signal-regulated kinase (ERK) and Jun N-terminal protein kinase (JNK) and phosphorylation and degradation of IκB in β4 mutant cells adhering to laminin-5. Unexpectedly, however, ERK, JNK, and NF-κB remain in the cytoplasm in β4 mutant cells on laminin-5, whereas they enter effectively into the nucleus in the same cells on fibronectin or in wild-type cells on both matrix proteins. Inhibitor studies indicate that α6β4 promotes keratinocyte proliferation and migration through its effect on NF-κB and P-JNK. These findings provide evidence that β4 signaling promotes epidermal growth and wound healing through a previously unrecognized effect on nuclear translocation of NF-κB and mitogen-activated protein kinases.


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