L. Mei et al., DIFFERENTIAL EXPRESSION OF PTP1D, A PROTEIN-TYROSINE-PHOSPHATASE WITH2 SH2 DOMAINS, IN SLOW AND FAST SKELETAL-MUSCLE FIBERS, Experimental cell research, 224(2), 1996, pp. 379-390
We show that PTP1D, a protein tyrosine phosphatase that contains two S
H2 domains, is preferentially expressed in slow skeletal muscle fibers
. Immunohistochemical staining using polyclonal antibodies against PTP
1D demonstrated that PTP1D was expressed in a subpopulation of rodent
muscle fibers. These fibers were identified as slow Type I fibers base
d on histochemical ATPase assays and slow myosin heavy chain expressio
n. Northern and Western analyses showed that PTP1D levels were higher
in predominantly slow muscles than in predominantly fast muscles. This
differential expression of PTP1D in slow muscle fibers appeared by bi
rth. In cultures of mouse myogenic cells, PTP1D was expressed after My
oD and myogenin and appeared in myotubes derived from embryonic, fetal
, and postnatal myoblasts. Remarkably, PTP1D was organized into sarcom
eres in a pattern coincident with myosin heavy chain, suggesting that
PTP1D associates with a component of the thick filament. These results
show that PTP1D is preferentially expressed in slow muscle fibers, We
speculate that PTP1D may play a role in slow muscle fiber function an
d differentiation. (C) 1996 Academic Press, Inc.