Myotonin-Protein Kinase (DMPK) Mouse Recombinant Protein

The protein encoded by this gene is a serine/threonine protein kinase that contains coiled-coil and C-terminal membrane association domains. In the embryonic mouse, it is found in cardiac and skeletal myocytes where it appears to play a role in myogenesis. In adults, the transcript is localized to several tissues including brain, heart, and skeletal and smooth muscle, and a function in cytoskeletal remodeling has been described. Transcripts with expanded CUG repeats in the 3' untranslated region mediate alternative splicing of several genes and sequester RNA binding proteins and RNA transcripts that contain CAG repeats, resulting in myotonic dystrophy, an autosomal dominant neuromuscular disorder. Alternative splicing results in multiple protein coding and non-coding transcript variants. [provided by RefSeq, Oct 2014]

DMPK1: Non-receptor serine/threonine protein kinase which is necessary for the maintenance of skeletal muscle structure and function. May play a role in myocyte differentiation and survival by regulating the integrity of the nuclear envelope and the expression of muscle-specific genes. May also phosphorylate PPP1R12A and inhibit the myosin phosphatase activity to regulate myosin phosphorylation. Also critical to the modulation of cardiac contractility and to the maintenance of proper cardiac conduction activity probably through the regulation of cellular calcium homeostasis. Phosphorylates PLN, a regulator of calcium pumps and may regulate sarcoplasmic reticulum calcium uptake in myocytes. May also phosphorylate FXYD1/PLM which is able to induce chloride currents. May also play a role in synaptic plasticity. Defects in DMPK are the cause of dystrophia myotonica type 1 (DM1); also known as Steinert disease. A muscular disorder characterized by myotonia, muscle wasting in the distal extremities, cataract, hypogonadism, defective endocrine functions, male baldness and cardiac arrhythmias. The causative mutation is a CTG expansion in the 3'-UTR of the DMPK gene. A length exceeding 50 CTG repeats is pathogenic, while normal individuals have 5 to 37 repeats. Intermediate alleles with 35-49 triplets are not disease-causing but show instability in intergenerational transmissions. Disease severity varies with the number of repeats: mildly affected persons have 50 to 150 repeats, patients with classic DM have 100 to 1,000 repeats, and those with congenital onset can have more than 2,000 repeats. Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. DMPK subfamily. 12 isoforms of the human protein are produced by alternative splicing.

Protein type: Kinase, protein; Membrane protein, integral; Protein kinase, Ser/Thr (non-receptor); Protein kinase, AGC; Mitochondrial; EC 2.7.11.1; AGC group; DMPK family; GEK subfamily

Cellular Component: endoplasmic reticulum membrane; sarcoplasmic reticulum membrane; nuclear membrane; mitochondrion; sarcoplasmic reticulum; endoplasmic reticulum; cell; integral to membrane; cytosol; mitochondrial outer membrane; membrane; cytoplasm; plasma membrane; intracellular; nucleus; integral to mitochondrial outer membrane

Molecular Function: transferase activity; protein serine/threonine kinase activity; myosin phosphatase regulator activity; protein binding; metal ion binding; heat shock protein binding; transferase activity, transferring phosphorus-containing groups; nucleotide binding; kinase activity; ATP binding; protein kinase activity

Biological Process: cellular calcium ion homeostasis; regulation of skeletal muscle contraction by calcium ion signaling; regulation of catalytic activity; regulation of synapse structural plasticity; regulation of excitatory postsynaptic membrane potential involved in skeletal muscle contraction; regulation of sodium ion transport; phosphorylation; protein amino acid phosphorylation; regulation of heart contraction; nuclear membrane organization and biogenesis