Protein kinase C activity modulates nuclear Lamin A/C dynamics in HeLa cells

Abstract

The nuclear lamina serves important functions in the nucleus, providing structural support to the nuclear envelope and contributing to chromatin organization. The primary proteins that constitute the lamina are nuclear lamins whose functions are impacted by post-translational modifications, including phosphorylation by protein kinase C (PKC). While PKC-mediated lamin phosphorylation is important for nuclear envelope breakdown during mitosis, less is known about interphase roles for PKC in regulating nuclear structure. Here we show that overexpression of PKC ß, but not PKC α, increases the Lamin A/C mobile fraction in the nuclear envelope in HeLa cells without changing the overall structure of Lamin A/C and Lamin B1 within the nuclear lamina. Conversely, knockdown of PKC ß, but not PKC α, reduces the Lamin A/C mobile fraction. Thus, we demonstrate an isoform-specific role for PKC in regulating interphase Lamin A/C dynamics outside of mitosis.