TY - JOUR
T1 - The myosin-bound form of protein phosphatase 1 (PP-1M) is the enzyme that dephosphorylates native myosin in skeletal and cardiac muscles
AU - Chisholm, Alexander A K
AU - Cohen, Philip
PY - 1988/9/16
Y1 - 1988/9/16
N2 - The myosin-bound form of protein phosphatase 1 (PP-1M) and the glycogen-bound form (PP-1G) together account for virtually all the phosphatase activity in rabbit skeletal muscle extracts towards native myosin. PP-1M has a 3-fold higher activity towards native myosin than does PP-1G and accounts for at least 60% of the myosin phosphatase activity in rabbit skeletal muscle. PP-1M accounts for 90% of the myosin phosphatase activity in bovine cardiac muscle, where PP-1G is essentially absent. The high activity of PP-1M towards native myosin appears to arise from interaction of the catalytic subunit with the putative myosin-binding subunit, since chymotryptic digestion liberates a catalytic subunit having the same characteristics as that released by limited proteolysis of PP-1G. Protein phosphatase 2A in skeletal and cardiac muscles is very active towards the isolated myosin P-light chain, but ineffective in dephosphorylating native myosin. The results suggest that PP-1M is the enzyme that dephosphorylates myosin in skeletal and cardiac muscle.
AB - The myosin-bound form of protein phosphatase 1 (PP-1M) and the glycogen-bound form (PP-1G) together account for virtually all the phosphatase activity in rabbit skeletal muscle extracts towards native myosin. PP-1M has a 3-fold higher activity towards native myosin than does PP-1G and accounts for at least 60% of the myosin phosphatase activity in rabbit skeletal muscle. PP-1M accounts for 90% of the myosin phosphatase activity in bovine cardiac muscle, where PP-1G is essentially absent. The high activity of PP-1M towards native myosin appears to arise from interaction of the catalytic subunit with the putative myosin-binding subunit, since chymotryptic digestion liberates a catalytic subunit having the same characteristics as that released by limited proteolysis of PP-1G. Protein phosphatase 2A in skeletal and cardiac muscles is very active towards the isolated myosin P-light chain, but ineffective in dephosphorylating native myosin. The results suggest that PP-1M is the enzyme that dephosphorylates myosin in skeletal and cardiac muscle.
KW - Muscle contraction
KW - Myosin
KW - Protein phosphatase
KW - Protein phosphorylation
KW - Striated muscle
UR - http://www.scopus.com/inward/record.url?scp=0023694199&partnerID=8YFLogxK
U2 - 10.1016/0167-4889(88)90188-7
DO - 10.1016/0167-4889(88)90188-7
M3 - Article
C2 - 2844285
AN - SCOPUS:0023694199
SN - 0167-4889
VL - 971
SP - 163
EP - 169
JO - Biochimica et Biophysica Acta (BBA) - Molecular Cell Research
JF - Biochimica et Biophysica Acta (BBA) - Molecular Cell Research
IS - 2
ER -