GIT1 mediates HDAC5 activation by angiotensin II in vascular smooth muscle cells.
OBJECTIVE
The G protein-coupled receptor (GPCR)-kinase2 interacting protein1 (GIT1) is a scaffold protein involved in angiotensin II (Ang II) signaling. Histone deacetylase-5 (HDAC5) has emerged as an important substrate of calcium/calmodulin-dependent protein kinase II (CamK II) in GPCR signaling. Here we investigated the hypothesis that Ang II-mediated vascular smooth muscle cell (VSMC) gene transcription involves GIT1-CamK II-dependent phosphorylation of HDAC5.


RESULTS
Ang II rapidly stimulated phosphorylation of HDAC5 at Ser498 in VSMCs. Knockdown of GIT1 significantly decreased HDAC5 phosphorylation induced by Ang II. The involvement of Src, phospholipase gamma (PLCgamma), and CamK II in GIT1-mediated HDAC5 phosphorylation was demonstrated. The association of GIT1 and CamK II was constitutive but increased after stimulation with Ang II. Moreover, the interaction of GIT1 and CamK II through the ARF GTPase-activating protein (ARF-GAP) and coiled-coil domains of GIT1 was essential for the phosphorylation of HDAC5. Finally, knockdown of GIT1 decreased myocyte enhancer factor 2 transcriptional activity induced by Ang II.


CONCLUSIONS
This study identifies a novel function for GIT1 as a mediator of Ang II-induced VSMC gene transcription via a Src-PLCgamma-CamK II-HDAC5 signaling pathway.
Pang
Jinjiang
J
Aab Cardiovascular Research Institute and the Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
Yan
Chen
C
Natarajan
Kanchana
K
Cavet
Megan E
ME
Massett
Michael P
MP
Yin
Guoyong
G
Berk
Bradford C
BC
D000804:Angiotensin II / Q000502:physiology*; D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D051966:Phospholipase C gamma / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D019061:src-Family Kinases
D018797:Cell Cycle Proteins; C485648:Git1 protein, rat; D010750:Phosphoproteins; D000804:Angiotensin II; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D051966:Phospholipase C gamma; C498619:Hdac5 protein, rat; D006655:Histone Deacetylases