DMPK Antibody – Rabbit

The protein encoded by this gene is a serine-threonine kinase that is closely related to other kinases that interact with members of the Rho family of small GTPases. Substrates for this enzyme include myogenin, the beta-subunit of the L-type calcium channels, and phospholemman. The 3' untranslated region of this gene contains 5-37 copies of a CTG trinucleotide repeat. Expansion of this unstable motif to 50-5,000 copies causes myotonic dystrophy type I, which increases in severity with increasing repeat element copy number. Repeat expansion is associated with condensation of local chromatin structure that disrupts the expression of genes in this region. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined. [provided by RefSeq, Jul 2008]

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

Chromosomal Location of Human Ortholog: 19q13.3

Cellular Component: nuclear outer membrane; endoplasmic reticulum membrane; nuclear membrane; sarcoplasmic reticulum membrane; plasma membrane; cytosol; integral to mitochondrial outer membrane

Molecular Function: protein serine/threonine kinase activity; myosin phosphatase regulator activity; protein binding; metal ion binding; ATP binding

Biological Process: cellular calcium ion homeostasis; regulation of catalytic activity; protein amino acid phosphorylation; nuclear membrane organization and biogenesis; regulation of heart contraction

Disease: Myotonic Dystrophy 1