Protein Kinase D1 mediates Class IIa Histone Deacetylase Phosphorylation and Nuclear Extrusion in Intestinal Epithelial Cells: Role in Mitogenic Signaling.

We examined whether class IIa histone deacetylases (HDACs) play a role in mitogenic signaling mediated by protein kinase D1 (PKD1) in IEC-18 intestinal epithelial cells. Our results show that class IIa HDAC 4, 5 and 7 are prominently expressed in these cells. Simulation with angiotensin II (ANG II), a potent mitogen for IEC-18 cells, induced a striking increase in the phosphorylation of HDAC4 at Ser(246) and Ser(632), HDAC5 at Ser(259) and Ser(498) and HDAC7 at Ser(155). Treatment with the PKD family inhibitors kb NB 142-70 and CRT0066101 or siRNA-mediated knockdown of PKD1 prevented ANG II-induced phosphorylation of HDAC 4, 5 and 7. A variety of PKD1 activators in IEC-18 cells, including vasopressin, lysophosphatidic acid or phorbol esters, also induced HDAC4, 5 and 7 phosphorylation. Using endogenously and ectopically expressed HDAC5, we show that PKD1-mediated phosphorylation of HDAC5 induces its nuclear extrusion into the cytoplasm. In contrast, HDAC5 with Ser(259) and Ser(498) mutated to Ala was localized to the nucleus in both unstimulated and stimulated cells. Treatment of IEC-18 cells with specific inhibitors of class IIa HDACs, including MC1568 and TMP269, prevented cell cycle progression, DNA synthesis and proliferation induced in response to GPCR/PKD1 activation. The PKD1/class IIa HDAC axis also functions in intestinal epithelial cell in vivo, since an increase in the phosphorylation of HDAC4/5 and HDAC7 was demonstrated in lysates of cryptal cells from PKD1 trans...

Source: Am J Physiol Cell Ph... - March 19, 2014 Category: Cytology Authors: Sinnett-Smith J, Ni Y, Wang J, Ming M, Young SH, Rozengurt E Tags: Am J Physiol Cell Physiol Source Type: research