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CaMKII Involvement in the Localization of iNOS in Vascular Smooth Muscle
Author(s) -
Jones Rachel,
Jourd’heuil David,
Smith Susan,
Salerno John,
Singer Harold
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a406
Subject(s) - ionomycin , colocalization , microbiology and biotechnology , vascular smooth muscle , immunofluorescence , chemistry , confocal microscopy , biology , intracellular , endocrinology , immunology , smooth muscle , antibody
iNOS expression is regulated transcriptionally in response to cytokine induction and post‐translationally by palmitoylation and trafficking into perinuclear aggresomes. We investigated the effects of CaMKII on iNOS induction and trafficking in cultured rat aortic vascular smooth muscle cells (VSMC). Immunofluorescence and confocal microscopy demonstrated colocalization of iNOS and CaMKIId2 with a perinuclear distribution. Furthermore, CaMKIId2 coimmunoprecipitated with iNOS and incubation with KN‐93 (a CaMKII inhibitor) facilitated this association, while causing a decrease in total iNOS activity. Addition of PDGF, UTP, and ionomycin increased the nuclear iNOS, as shown by immunofluorescence and confocal microscopy. Adenoviral expression of a constitutively active CaMKII mutant also increased nuclear iNOS immunofluorescence staining and markedly translocated iNOS from a membrane to a nuclear fraction. Knockdown of CaMKII using an adenovirus expressing a short hairpin siRNA increased nuclear iNOS localization in resting cells, but inhibited ionomycin‐induced translocation of iNOS to the nucleus. Cells expressing little CaMKII demonstrated altered iNOS localization with fewer aggresome‐like structures. The results suggest that CaMKII may be an important regulator of iNOS trafficking and localization in VSMCs.