Activation of protein kinase C delta by psi delta RACK peptide promotes embryonic stem cell proliferation through ERK 1/2

Author(s)

Garavello, Nicole Milare ^[1] ; Pena, Darlene Aparecida ^[1] ; Camargo Bonatto, Jose Matheus ^[1] ; Duarte, Mariana Lemos ^[1] ; Costa-Junior, Helio Miranda ^[2] ; Schumacher, Robert Ivan ^[1] ; Forti, Fabio Luis ^[1] ; Schechtman, Deborah ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-05508 Sao Paulo - Brazil

^[2] HCFMUSP, Fac Med, Inst Coracao, Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF PROTEOMICS; v. 94, p. 497-512, DEC 6 2013.
• Web of Science Citations: 5

Abstract

The protein kinase C (PKC) family of serine/threonine kinases participate in embryonic stem cell (ESC) proliferation/self-renewal. A few stimuli that induce ESC proliferation activate several PKC isoenzymes including delta PKC, however, the role of this isoenzyme under basal conditions that maintain undifferentiated ESCs remains to be determined. Herewith, we aimed to characterize signaling events that occur in undifferentiated ESCs upon delta PKC activation. Using phosphoproteomics and a delta PKC specific activator peptide, psi delta RACK, it was seen that the majority of proteins whose phosphorylation increased upon delta PKC activation participate in cell proliferation. Network analysis of these proteins directly connected delta PKC to Raf1 and 14-3-3. Experimental validation studies showed that activation of delta PKC increased its binding to 14-3-3, transiently activated ERK1/2 and increased ESC proliferation. Independently inhibiting MEK or PI3 kinase both led to a decrease in proliferation of approximately 50%, but delta PKC activation only recovered the effect of PI3 kinase inhibition suggesting that ERK1/2 activation via delta PKC is probably a parallel pathway to PI3 kinase and that both pathways are necessary for undifferentiated ESC proliferation. Biological significance The use of embryonic stem cells and induced pluripotent stem cells for regenerative therapies is still a challenge. Understanding the underlying mechanisms that keep these cells proliferating with the ability to differentiate in more than 200 cell types (self-renewal) will aid in the future use of these cells therapeutically. Using a targeted phosphoproteomics study, insights into signaling pathways involved in ESC proliferation can be obtained. Modulating these pathways will aid the obtention of a larger number of self-renewing stem cells and induced pluripotent stem cells that can be used therapeutically. (C) 2013 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 10/18640-8 - PKC and signal transduction pathways of self-renewal and differentiation in murine embryonic stem cells
• Grantee: Deborah Schechtman
• Support type: Regular Research Grants
• FAPESP's process: 11/10321-3 - Functional characterization of protein kinase c beta 1 in self-renewal
• Grantee: Darlene Aparecida Pena
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 10/08798-3 - Characterization of nuclear protein kinase C beta I of murine embryonic stem cells
• Grantee: José Matheus Camargo Bonatto
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/04067-7 - Caracterization of the role of PKCs in proliferation and self-renewal in murine embryonic stem cells
• Grantee: Nicole Milaré Garavello
• Support type: Scholarships in Brazil - Master