Phosphorylation of multiple sites in a 15,000 dalton proteolipid from rat skeletal muscle sarcolemma, catalyzed by adenosine 3',5'-monophosphate-dependent and calcium/phospholipid-dependent protein kinases.
Biochim Biophys Acta
; 968(1): 127-37, 1988 Jan 18.
Article
in En
| MEDLINE
| ID: mdl-3337842
ABSTRACT
This study reports a partial characterization of a 15,000 dalton (15 kDa) proteolipid present in rat skeletal muscle sarcolemma. The proteolipid is phosphorylated by both cyclic AMP-dependent and calcium/phospholipid-dependent protein kinases, displays an isoelectric point (pI) of 5.9, and can be extracted from sarcolemma by acidified chloroform/methanol (21) or non-ionic detergents. Phosphoamino acid analysis and tryptic fingerprinting of the phosphorylated proteolipid indicate that both cyclic AMP- and calcium/phospholipid-dependent protein kinases predominantly phosphorylate serine residue(s) on a single tryptic peptide. Additivity experiments and thermolytic fingerprinting demonstrate a minimum of two distinct phosphorylation sites on the proteolipid, the phosphorylation of which is independently catalyzed by cyclic AMP-dependent and calcium/phospholipid-dependent protein kinases in vitro. This sarcolemma proteolipid, which appears to be identified to a sarcolemma protein previously reported to be phosphorylated upon addition of insulin in a GTP-dependent manner (Walaas, O., Walaas, E., Rye-Alertsen, A. and Horn, R.S. (1979) Mol. Cell. Endocrinol. 16, 45-55), therefore represents a possible membrane target for those neuronal and hormonal stimuli which can regulate cyclic AMP-dependent or calcium/phospholipid-dependent protein kinase activities in skeletal muscle.
Search on Google
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Protein Kinases
/
Proteolipids
/
Sarcolemma
/
Protein Kinase C
/
Muscles
Limits:
Animals
Language:
En
Journal:
Biochim Biophys Acta
Year:
1988
Document type:
Article