Adenylate Kinase 2 (AK2) Human Active Protein

Adenylate kinases are involved in regulating the adenine nucleotide composition within a cell by catalyzing the reversible transfer of phosphate groups among adenine nucleotides. Three isozymes of adenylate kinase, namely 1, 2, and 3, have been identified in vertebrates; this gene encodes isozyme 2. Expression of these isozymes is tissue-specific and developmentally regulated. Isozyme 2 is localized in the mitochondrial intermembrane space and may play a role in apoptosis. Mutations in this gene are the cause of reticular dysgenesis. Alternate splicing results in multiple transcript variants. Pseudogenes of this gene are found on chromosomes 1 and 2.[provided by RefSeq, Nov 2010]

AK2: Catalyzes the reversible transfer of the terminal phosphate group between ATP and AMP. This small ubiquitous enzyme involved in energy metabolism and nucleotide synthesis that is essential for maintenance and cell growth. Plays a key role in hematopoiesis. Defects in AK2 are the cause of reticular dysgenesis (RDYS); also known as aleukocytosis. RDYS is the most severe form of inborn severe combined immunodeficiencies (SCID) and is characterized by absence of granulocytes and almost complete deficiency of lymphocytes in peripheral blood, hypoplasia of the thymus and secondary lymphoid organs, and lack of innate and adaptive humoral and cellular immune functions, leading to fatal septicemia within days after birth. In bone marrow of individuals with reticular dysgenesis, myeloid differentiation is blocked at the promyelocytic stage, whereas erythro- and megakaryocytic maturation is generally normal.In addition, affected newborns have bilateral sensorineural deafness. Defects may be due to its absence in leukocytes and inner ear, in which its absence can not be compensated by AK1. Belongs to the adenylate kinase family. AK2 subfamily. 6 isoforms of the human protein are produced by alternative splicing.

Protein type: Nucleotide Metabolism - purine; EC 2.7.4.3; Mitochondrial; Kinase, other

Chromosomal Location of Human Ortholog: 1p34

Cellular Component: mitochondrial inner membrane; mitochondrial intermembrane space; cytosol

Molecular Function: adenylate kinase activity; ATP binding

Biological Process: dATP metabolic process; nucleobase, nucleoside and nucleotide interconversion; nucleobase, nucleoside and nucleotide metabolic process; ADP biosynthetic process; brain development; liver development; AMP metabolic process; oxidative phosphorylation; nucleotide phosphorylation

Disease: Reticular Dysgenesis