Protein kinase domain;

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gi 922582286    2 LDSEIYDFMKATLKIDPKKRKSAIDVLKMPLF 33
Cdd:pfam00069 186 LSEEAKDLLKKLLKKDPSKRLTATQALQHPWF 217

Catalytic domain of Male germ cell-Associated Kinase-like Serine/Threonine Kinases; STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. This subfamily is composed of human MAK and MAK-related kinase (MRK), Saccharomyces cerevisiae Ime2p, Schizosaccharomyces pombe Mei4-dependent protein 3 (Mde3) and Pit1, Caenorhabditis elegans dyf-5, Arabidopsis thaliana MHK, and similar proteins. These proteins play important roles during meiosis. MAK is highly expressed in testicular cells specifically in the meiotic phase, but is not essential for spermatogenesis and fertility. It functions as a coactivator of the androgen receptor in prostate cells. MRK, also called Intestinal Cell Kinase (ICK), is expressed ubiquitously, with highest expression in the ovary and uterus. A missense mutation in MRK causes endocrine-cerebro-osteodysplasia, suggesting that this protein plays an important role in the development of many organs. MAK and MRK may be involved in regulating cell cycle and cell fate. Ime2p is a meiosis-specific kinase that is important during meiotic initiation and during the later stages of meiosis. Mde3 functions downstream of the transcription factor Mei-4 which is essential for meiotic prophase I. The MAK-like subfamily is part of a larger superfamily that includes the catalytic domains of other STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.

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gi 922582286   8 DFMKATLKIDPKKRKSAIDVLKMPLF 33
Cdd:cd07830  258 DLIKDMLRWDPKKRPTASQALQHPYF 283

Catalytic domain of Cyclin-Dependent protein Kinase-like Serine/Threonine Kinases; STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. CDKs belong to a large family of STKs that are regulated by their cognate cyclins. Together, they are involved in the control of cell-cycle progression, transcription, and neuronal function. CDKs are partly regulated by their subcellular localization, which defines substrate phosphorylation and the resulting specific function. CDK1, CDK2, CDK4, and CDK6 have well-defined functions in the cell cycle, such as the regulation of the early G1 phase by CDK4 or CDK6, the G1/S phase transition by CDK2, or the entry of mitosis by CDK1. They also exhibit overlapping cyclin specificity and functions in certain conditions. Knockout mice with a single CDK deleted remain viable with specific phenotypes, showing that some CDKs can compensate for each other. For example, CDK4 can compensate for the loss of CDK6, however, double knockout mice with both CDK4 and CDK6 deleted die in utero. CDK8 and CDK9 are mainly involved in transcription while CDK5 is implicated in neuronal function. CDK7 plays essential roles in both the cell cycle as a CDK-Activating Kinase (CAK) and in transcription as a component of the general transcription factor TFIIH. The CDK-like subfamily is part of a larger superfamily that includes the catalytic domains of other STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.

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gi 922582286   2 LDSEIYDFMKATLKIDPKKRKSAIDVLKMPLF 33
Cdd:cd07829  251 LDPEGIDLLSKMLQYNPAKRISAKEALKHPYF 282

Pseudokinase domain, repeat 1, of eukaryotic translation Initiation Factor 2-Alpha Kinase 4 or General Control Non-derepressible-2; The pseudokinase domain shows similarity to protein kinases but lacks crucial residues for catalytic activity. EIF2AKs phosphorylate the alpha subunit of eIF-2, resulting in the overall downregulation of protein synthesis. eIF-2 phosphorylation is induced in response to cellular stresses including virus infection, heat shock, nutrient deficiency, and the accummulation of unfolded proteins, among others. There are four distinct kinases that phosphorylate eIF-2 and control protein synthesis under different stress conditions: GCN2, protein kinase regulated by RNA (PKR), heme-regulated inhibitor kinase (HRI), and PKR-like endoplasmic reticulum kinase (PERK). GCN2 is activated by amino acid or serum starvation and UV irradiation. It induces GCN4, a transcriptional activator of amino acid biosynthetic genes, leading to increased production of amino acids under amino acid-deficient conditions. In serum-starved cells, GCN2 activation induces translation of the stress-responsive transcription factor ATF4, while under UV stress, GCN2 triggers transcriptional rescue via NF-kappaB signaling. GCN2 contains an N-terminal RWD, a degenerate kinase-like (repeat 1), the catalytic kinase (repeat 2), a histidyl-tRNA synthetase (HisRS)-like, and a C-terminal ribosome-binding and dimerization (RB/DD) domains. The degenerate pseudokinase domain of GCN2 may function as a regulatory domain. The GCN2 subfamily is part of a larger superfamily that includes the catalytic domains of serine/threonine kinases, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.

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gi 922582286   2 LDSEIYDFMKATLKIDPKKRKSAIDVLKMP 31
Cdd:cd14012  224 LSASLQDFLSKCLSLDPKKRPTALELLPHE 253