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Fig. 3. AKAP149 is as a B-type lamin-specifier of PP1. (A) AKAP149-IPs were
incubated with phosphorylase a and either 1 µM trypsin, 50 µM
KNSRVTFSED (`RVXF') peptide, 50 µM KNSRATASED (`RAXA')
peptide, or 1 µM I-2. Phosphorylase phosphatase activity was evaluated as
the release of 32P measured by scintillation counting and expressed
as a percentage (±s.d.) of activity after trypsinization in duplicate
experiments. (B) AKAP149-IPs were incubated with immunoprecipitated B-type
lamins phosphorylated in vitro with rat
ß
PKC and
[
32P]ATP. B-type lamin phosphatase activity was measured as
in (A) in duplicate experiments. 50 µM SSPKGVLFSS (`RVXF') or
SSPKGALFSS (`RAXF') peptides were used.