Association of PP1 with Its Regulatory Subunit AKAP149 Is Regulated by Serine Phosphorylation Flanking the RVXF Motif of AKAP149
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- 作者：Thomas Kü ; ntziger ; Marie Rogne ; Rikke L. S. Folstad ; and Philippe Collas
- 刊名：Biochemistry
- 出版年：2006
- 出版时间：May 9, 2006
- 年：2006
- 卷：45
- 期：18
- 页码：5868 - 5877
- 全文大小：395K
- 年卷期：v.45,no.18(May 9, 2006)
- ISSN：1520-4995
文摘
Reformation of the nuclear envelope at the end of mitosis involves the recruitment of theB-type lamin phosphatase PP1 to nuclear membranes by A-kinase anchoring protein AKAP149. PP1remains associated to AKAP149 throughout G1 but dissociates from AKAP149 when AKAP149 isphosphorylated at the G1/S transition. We examine here the role of phosphorylation of serines flankingthe RVXF PP1-binding motif of AKAP149, on PP1 anchoring. The use of AKAP149 peptides encompassingthe RVXF motif and five flanking serines, either wild type (wt) or bearing S
A or SD mutations,specifically shows that phosphorylation of S151 or S159 abolishes PP1 binding to immobilized AKAP149.Peptides with S151 or S159 as the only wt serine residue trigger dissociation of PP1 from immunoprecipitated AKAP149, whereas S151/159D mutants are ineffective. Furthermore, immunoprecipitatedAKAP149 from purified G1-phase nuclear envelopes binds PKA and PKC in overlay assays. PKA bindingto AKAP149 in vitro is unaffected by the presence of PKC or PP1, and similarly, PKC binding isindependent of PKA or PP1. The immunoprecipitated AKAP149 complex contains PKA and PKC activities.Both AKAP149-associated PKA and PKC serine-phosphorylate immunoprecipitated AKAP149 in vitro;however, only PKC-mediated phosphorylation promotes dissociation of PP1 from the AKAP. The resultssuggest a putative temporally and spatially controlled mechanism promoting release of PP1 from AKAP149.AKAP149 emerges as a scaffolding protein for multiple protein kinases and phosphatases that may beinvolved in the integration of intracellular signals that converge at the nuclear envelope.
A or SD mutations,specifically shows that phosphorylation of S151 or S159 abolishes PP1 binding to immobilized AKAP149.Peptides with S151 or S159 as the only wt serine residue trigger dissociation of PP1 from immunoprecipitated AKAP149, whereas S151/159D mutants are ineffective. Furthermore, immunoprecipitatedAKAP149 from purified G1-phase nuclear envelopes binds PKA and PKC in overlay assays. PKA bindingto AKAP149 in vitro is unaffected by the presence of PKC or PP1, and similarly, PKC binding isindependent of PKA or PP1. The immunoprecipitated AKAP149 complex contains PKA and PKC activities.Both AKAP149-associated PKA and PKC serine-phosphorylate immunoprecipitated AKAP149 in vitro;however, only PKC-mediated phosphorylation promotes dissociation of PP1 from the AKAP. The resultssuggest a putative temporally and spatially controlled mechanism promoting release of PP1 from AKAP149.AKAP149 emerges as a scaffolding protein for multiple protein kinases and phosphatases that may beinvolved in the integration of intracellular signals that converge at the nuclear envelope.