Differential expression of PTP1D, a protein tyrosine phosphatase with two SH2 domains, in a slow and fast skeletal muscle fibers.
We show that PTP1D, a protein tyrosine phosphatase that contains two SH2 domains, is preferentially expressed in slow skeletal muscle fibers. Immunohistochemical staining using polyclonal antibodies against PTP1D demonstrated that PTP1D was expressed in a subpopulation of rodent muscle fibers. These fibers were identified as slow Type I fibers based on histochemical ATPase assays and slow myosin heavy chain expression. 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 birth. In cultures of mouse myogenic cells, PTP1D was expressed after MyoD and myogenin and appeared in myotubes derived from embryonic, fetal, and postnatal myoblasts. Remarkably, PTP1D was organized into sarcomeres 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 and differentiation.
Mei
L
L
Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville 22908, USA.
Kachinsky
A M
AM
Seiden
J E
JE
Kuncl
R W
RW
Miller
J B
JB
Huganir
R L
RL
D000818:Animals; D000918:Antibody Specificity; D015152:Blotting, Northern; D015153:Blotting, Western; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D018656:Muscle Fibers, Fast-Twitch / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure; D018657:Muscle Fibers, Slow-Twitch / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000166:cytology; D018995:Myosin Heavy Chains / Q000032:analysis / Q000096:biosynthesis; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D012518:Sarcomeres / Q000737:chemistry / Q000502:physiology; D018909:src Homology Domains / Q000235:genetics*
D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C516727:Ptpn11 protein, rat; C509248:Ptpn6 protein, mouse; C509250:Ptpn6 protein, rat; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D018995:Myosin Heavy Chains