The Cytoplasmic Domain of α6A Integrin Subunit Is an in Vitro Substrate for Protein Kinase C

1995 ◽  
Vol 216 (1) ◽  
pp. 232-235 ◽  
Author(s):  
Clotilde Gimond ◽  
Annemieke de Melker ◽  
Monique Aumailley ◽  
Arnoud Sonnenberg
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cytoplasmic Domain ◽  
Integrin Subunit ◽  
Kinase C

scholarly journals Syndecan-4 regulates localization, activity and stability of protein kinase C-alpha

2004 ◽  
Vol 378 (3) ◽  
pp. 1007-1014 ◽  
Author(s):  
Eunyoung KEUM ◽  
Yeonhee KIM ◽  
Jungyean KIM ◽  
Soojin KWON ◽  
Yangmi LIM ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Heparan Sulphate ◽  
Critical Role ◽  
Focal Adhesions ◽  
Cytoplasmic Domain ◽  
Prolonged Treatment ◽  
Kinase C

During cell–matrix adhesion, syndecan-4 transmembrane heparan sulphate proteoglycan plays a critical role in the formation of focal adhesions and stress fibres. We have shown previously that the syndecan-4 cytoplasmic domain directly binds to and activates PKC-α (protein kinase C-α) in vitro [Oh, Woods and Couchman (1997) J. Biol. Chem. 272, 8133–8136]. However, whether syndecan-4 has the same activity in vivo needs to be addressed. Using mammalian two-hybrid assays, we showed that syndecan-4 interacted with PKC-α in vivo and that this interaction was mediated through syndecan-4 cytoplasmic domain. Furthermore, the activation of PKC increased the extent of interaction between syndecan-4 and PKC-α. Overexpression of syndecan-4, but not a mutant lacking its cytoplasmic domain, specifically increased the level of endogenous PKC-α and enhanced the translocation of PKC-α into both detergent-insoluble and membrane fractions. In addition, rat embryo fibroblasts overexpressing syndecan-4 exhibited a slowed down-regulation of PKC-α in response either to a prolonged treatment with PMA or to maintaining cells in suspension culture. PKC-α immunocomplex kinase assays also showed that syndecan-4 overexpression increased the activity of membrane PKC-α. Taken together, these results suggest that syndecan-4 interacts with PKC-α in vivo and regulates its localization, activity and stability.

scholarly journals N-Acetylcysteine and α-cyano-4-hydroxycinnamic acid alter protein kinase C (PKC)-δ and PKC-ζ and diminish dysmorphogenesis in rat embryos cultured with high glucose in vitro

2007 ◽  
Vol 192 (1) ◽  
pp. 207-214 ◽  
Author(s):  
Mattias Gäreskog ◽  
Parri Wentzel
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
High Glucose ◽  
Culture Medium ◽  
Hydroxycinnamic Acid ◽  
Oxygen Species ◽  
Rat Embryos ◽  
Protein Kinase C Inhibitors ◽  
Kinase C

Malformations and growth disturbances are two- to threefold more common in infants of diabetic mothers than in offspring of non-diabetic pregnancy. Several suggestions have emerged to explain the reasons for diabetic embryopathy, including enhanced mitochondrial production of reactive oxygen species leading to altered activation of protein kinase C. This study aimed to evaluate the effect of α-cyano-4-hydroxycinnamic acid (CHC) and N-acetylcysteine (NAC) addition on morphology and activity of protein kinase C-δ and protein kinase C-ζ in rat embryos exposed to a high glucose concentration in vitro. Day 9 embryos from normal rats were cultured in 10 or 30 mM glucose concentrations with or without supplementation of CHC, NAC, or protein kinase C inhibitors specific for protein kinase C-δ and protein kinase C-ζ. Embryos were evaluated for malformations, crown rump length, and somite number. Protein kinase C-δ and protein kinase C-ζ activities were estimated by western blot by separating membranous and cytosolic fractions of the embryo. We found increased malformations and growth retardation in embryos cultured in high versus low glucose concentrations. These abnormalities were diminished when CHC and NAC or specific protein kinase C-inhibitors were added to the culture medium. The activities of embryonic protein kinase C-δ and protein kinase C-ζ were increased in the high glucose environment after 24-h culture, but were normalized by the addition of CHC and NAC as well as respective inhibitor to the culture medium. These findings suggest that mitochondrial overproduction of reactive oxygen species is involved in diabetic embryopathy. Furthermore, such overproduction may affect embryonic development, at least partly, by enhancing the activities of protein kinase C-δ and protein kinase C-ζ.

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