Identification of three cAMP-dependent protein kinase (PKA) phosphorylation sites within the major intracellular domain of neuronal nicotinic receptor α4 subunits

2002 ◽  
Vol 82 (2) ◽  
pp. 439-447 ◽  
Author(s):  
Xiang Guo ◽  
Lynn Wecker
Keyword(s):  
Protein Kinase ◽  
Nicotinic Receptor ◽  
Phosphorylation Sites ◽  
Dependent Protein Kinase ◽  
Intracellular Domain ◽  
Neuronal Nicotinic Receptor ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

Adjacent phosphorylation sites on GABAA receptor β subunits determine regulation by cAMP-dependent protein kinase

10.1038/223 ◽  
1998 ◽  
Vol 1 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Bernard J. McDonald ◽  
Alessandra Amato ◽  
Christopher N. Connolly ◽  
Dietmar Benke ◽  
Stephen J. Moss ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Gabaa Receptor ◽  
Phosphorylation Sites ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

scholarly journals Protein kinase C and cyclic AMP-dependent protein kinase phosphorylate phospholemman, an insulin and adrenaline-regulated membrane phosphoprotein, at specific sites in the carboxy terminal domain

1994 ◽  
Vol 304 (2) ◽  
pp. 635-640 ◽  
Author(s):  
S I Walaas ◽  
A J Czernik ◽  
O K Olstad ◽  
K Sletten ◽  
O Walaas
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Striated Muscle ◽  
Protein A ◽  
Phosphorylation Sites ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Kinase C ◽  
Dependent Protein

Phospholemman, a transmembrane, 72 residue protein enriched in striated muscle and heart [Palmer, Scott and Jones (1991) J. Biol. Chem. 266, 11126-11130], is phosphorylated in response to insulin [Walaas, Horn and Walaas (1991) Biochim. Biophys. Acta 1094, 92-102]. The present study is aimed at identifying the phosphorylation sites of this protein. A synthetic peptide, GTFRSS63IRRLS68TRRR (in the single letter code) and consisting of phospholemman residues 58-72, is a substrate for both protein kinase C and cyclic AMP (cAMP)-dependent protein kinase, with Km values of 6-7 microM for both enzymes. Amino acid sequencing of the phosphopeptide shows that protein kinase C phosphorylates both Ser-63 and Ser-68, while cAMP-dependent protein kinase phosphorylates Ser-68. Thermolytic phosphopeptide mapping of 32P-labelled phospholemman from rat diaphragms shows that treatment with insulin results in labelling of phosphopeptides containing both Ser-63 and Ser-68, whereas treatment with adrenaline results in labelling of the phosphopeptide containing Ser-68. Hence, insulin and adrenaline regulate the phosphorylation of phospholemman, presumably through protein kinase C and cAMP-dependent protein kinase, respectively, on partly overlapping phosphorylation sites.

scholarly journals Phosphorylation of native and reassembled neurofilaments composed of NF-L, NF-M, and NF-H by the catalytic subunit of cAMP-dependent protein kinase.

1994 ◽  
Vol 5 (2) ◽  
pp. 161-172 ◽  
Author(s):  
S Hisanaga ◽  
Y Matsuoka ◽  
K Nishizawa ◽  
T Saito ◽  
M Inagaki ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Catalytic Subunit ◽  
Phosphorylation Sites ◽  
Electron Microscopic ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Head Domain ◽  
Dependent Protein ◽  
Oligomeric Forms ◽  
Kinase A

Phosphorylation of neurofilament-L protein (NF-L) by the catalytic subunit of cAMP-dependent protein kinase (A-kinase) inhibits the reassembly of NF-L and disassembles filamentous NF-L. The effects of phosphorylation by A-kinase on native neurofilaments (NF) composed of three distinct subunits: NF-L, NF-M, and NF-H, however, have not yet been described. In this paper, we examined the effects of phosphorylation of NF proteins by A-kinase on both native and reassembled filaments containing all three NF subunits. In the native NF, A-kinase phosphorylated each NF subunit with stoichiometries of 4 mol/mol for NF-L, 6 mol/mol for NF-M, and 4 mol/mol for NF-H. The extent of NF-L phosphorylation in the native NF was nearly the same as that of purified NF-L. However, phosphorylation did not cause the native NFs to disassemble into oligomers, as was the case for purified NF-L. Instead, partial fragmentation was detected in sedimentation experiments and by electron microscopic observations. This is probably not due to the presence of the three NF subunits in NF or to differences in phosphorylation sites because reassembled NF containing all three NF subunits were disassembled into oligomeric forms by phosphorylation with A-kinase and the phosphorylation by A-kinase occurred at the head domain of NF-L whether NF were native or reassembled. Disassembling intermediates of reassembled NF containing all three NF subunits were somewhat different from disassembling intermediates of NF-L. Thinning and loosening of filaments was frequently observed preceding complete disassembly. From the fact that the thinning was also observed in the native filaments phosphorylated by A-kinase, it is reasonable to propose the native NF is fragmented through a process of thinning that is stimulated by phosphorylation in the head domain of the NF subunits.

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