SpermatogenesisOnline 1.0

Tag Content
SG ID
SG00013269 
UniProt Accession
Theoretical PI
6.37  
Molecular Weight
108303 Da  
Genbank Nucleotide ID
Genbank Protein ID
Gene Name
Hk1 
Gene Synonyms/Alias
 
Protein Name
Hexokinase-1 
Protein Synonyms/Alias
EC=2.7.1.1 Hexokinase type I;HK I Hexokinase, tumor isozyme; 
Organism
Mus musculus (Mouse) 
NCBI Taxonomy ID
10090 
Chromosome Location
chr:10;61731603-61842656;-1
View in Ensembl genome browser  
Function in Stage
Uncertain 
Function in Cell Type
Uncertain 
Probability (GAS) of Function in Spermatogenesis
0.751342229 
The probability was calculated by GAS algorithm, ranging from 0 to 1. The closer it is to 1, the more possibly it functions in spermatogenesis.
Description
Temporarily unavailable 
Abstract of related literatures
1. In rapidly growing tumor cells exhibiting high glucose catabolic rates, the enzyme hexokinase is markedly elevated and bound in large amounts (50-80% of the total cell activity) to the outer mitochondrial membrane (Arora, K.K., and Pedersen, P.L. (1988) J. Biol. Chem. 263, 17422-17428; Parry, D.M., and Pedersen, P.L. (1983) J. Biol. Chem. 258, 10904-10912). In extending these studies, we have isolated a cDNA clone of hexokinase from a lambda gt11 library of the highly glycolytic, c37 mouse hepatoma cell line. This clone, comprising 4,198 base pairs, contains a single open reading frame of 2,754 nucleotides which encode a 918-amino acid hexokinase with a mass of 102,272 daltons. This enzyme exhibits, respectively, 68 and 32 amino acid differences, including several charge differences, from the recently sequenced human kidney and rat brain enzymes. The putative glucose and ATP binding domains present in the latter two enzymes and in rat liver glucokinase are conserved in the tumor enzyme. At its N-terminal region, tumor hexokinase has a 12-amino acid hydrophobic stretch which is present in the rat brain enzyme but absent in the rat liver glucokinase, a cytoplasmic enzyme. The mature tumor hexokinase protein has been overexpressed in active form in Escherichia coli and purified 9-fold. The overexpressed enzyme binds to rat liver mitochondria in the presence of MgCl2. This is the first report describing the cloning and sequencing of a tumor hexokinase, and the first report documenting the overexpression of any hexokinase type in E. coli. Questions pertinent to the enzyme's mechanism, regulation, binding to mitochondria, and its marked elevation in tumor cells can now be addressed. PMID: [2318862] 

2. We have identified cDNAs representing three hexokinase mRNAs (Hk1-sa, Hk1-sb, Hk1-sc) by screening mouse spermatogenic cell cDNA libraries with a mouse hepatoma cell line hexokinase (Hk1) cDNA [Arora KK, Fanciulli M, Pederson PL. J Biol Chem 1990; 265:6481-6488]. Although all three cDNAs show 99% identity to the somatic Hk1 cDNA sequence throughout most of their coding region, they differ from this sequence at the 5' end. They contain a common spermatogenic cell-specific sequence and a sequence unique to each cDNA immediately 5' to the common domain. However, they lack the porin-binding domain (PBD) present in this region of Hk1, used for binding to a pore-forming protein in the outer mitochondrial membrane. These observations appear to support a model proposed by others for hexokinase gene evolution in mammals. In addition, we found that Hk1-sb has an internal sequence that is not present in Hk1, Hk1-sa, or Hk1-sc. Moreover, Hk1-sa and Hk1-sb transcripts are developmentally expressed in mouse spermatogenic cells. Hk1-sa mRNA is first expressed during meiosis and continues to be present in postmeiotic germ cells, while the more abundant Hk1-sb mRNA is detected only in postmeiotic germ cells. These and other findings suggest that enzymes encoded by Hk1-sa, Hk1-sb, and Hk1-sc are present only in spermatogenic cells. PMID: [8396993] 

3. The mouse (Mus musculus) is the premier animal model for understanding human disease and development. Here we show that a comprehensive understanding of mouse biology is only possible with the availability of a finished, high-quality genome assembly. The finished clone-based assembly of the mouse strain C57BL/6J reported here has over 175,000 fewer gaps and over 139 Mb more of novel sequence, compared with the earlier MGSCv3 draft genome assembly. In a comprehensive analysis of this revised genome sequence, we are now able to define 20,210 protein-coding genes, over a thousand more than predicted in the human genome (19,042 genes). In addition, we identified 439 long, non-protein-coding RNAs with evidence for transcribed orthologs in human. We analyzed the complex and repetitive landscape of 267 Mb of sequence that was missing or misassembled in the previously published assembly, and we provide insights into the reasons for its resistance to sequencing and assembly by whole-genome shotgun approaches. Duplicated regions within newly assembled sequence tend to be of more recent ancestry than duplicates in the published draft, correcting our initial understanding of recent evolution on the mouse lineage. These duplicates appear to be largely composed of sequence regions containing transposable elements and duplicated protein-coding genes; of these, some may be fixed in the mouse population, but at least 40% of segmentally duplicated sequences are copy number variable even among laboratory mouse strains. Mouse lineage-specific regions contain 3,767 genes drawn mainly from rapidly-changing gene families associated with reproductive functions. The finished mouse genome assembly, therefore, greatly improves our understanding of rodent-specific biology and allows the delineation of ancestral biological functions that are shared with human from derived functions that are not. PMID: [19468303] 

4. Multiple isoforms of type 1 hexokinase (HK1) are transcribed during spermatogenesis in the mouse, including at least three that are presumably germ cell specific: HK1-sa, HK1-sb, and HK1-sc. Each of these predicted proteins contains a common, germ cell-specific sequence that replaces the porin-binding domain found in somatic HK1. Although HK1 protein is present in mature sperm and is tyrosine phosphorylated, it is not known whether the various potential isoforms are differentially translated and localized within the developing germ cells and mature sperm. Using antipeptide antisera against unique regions of HK1-sa and HK1-sb, it was demonstrated that these isoforms were not found in pachytene spermatocytes, round spermatids, condensing spermatids, or sperm, suggesting that HK1-sa and HK1-sb are not translated during spermatogenesis. Immunoreactivity was detected in protein from round spermatids, condensing spermatids, and mature sperm using an antipeptide antiserum against the common, germ cell-specific region, suggesting that HK1-sc was the only germ cell-specific isoform present in these cells. Two-dimensional SDS-PAGE suggested that all of the sperm HK1-sc was tyrosine phosphorylated, and that the somatic HK1 isoform was not present. Immunoelectron microscopy revealed that HK1-sc was associated with the mitochondria and with the fibrous sheath of the flagellum and was found in discrete clusters in the region of the membranes of the sperm head. The unusual distribution of HK1-sc in sperm suggests novel functions, such as extramitochondrial energy production, and also demonstrates that a hexokinase without a classical porin-binding domain can localize to mitochondria. PMID: [9450953] 

5. Although three germ cell-specific transcripts of type 1 hexokinase exist in murine male germ cells, only one form, HK1-sc, is found at the protein level. This single isoform localizes to three distinct structures in mouse spermatozoa: the membranes of the head, the mitochondria in the midpiece, and the fibrous sheath in the flagellum (Travis, A. J., Foster, J. A., Rosenbaum, N. A., Visconti, P. E., Gerton, G. L., Kopf, G. S., and Moss, S. B. (1998) Mol. Biol. Cell 9, 263-276). The mechanism by which one protein is targeted to multiple sites within this highly polarized cell poses important questions of protein targeting. Because the study of protein targeting in germ cells is hampered by the lack of established cell lines in culture, constructs containing different domains of the germ cell-specific hexokinase transcripts were linked to a green fluorescent protein and transfected into hexokinase-deficient M+R42 cells. Constructs containing a nonhydrophobic, germ cell-specific domain, present at the amino terminus of the HK1-SC protein, were targeted to the endoplasmic reticulum and the plasma membrane. Mutational analysis of this domain demonstrated that a complex motif, PKIRPPLTE (with essential residues italicized), represented a novel endoplasmic reticulum-targeting motif. Constructs based on another germ cell-specific hexokinase transcript, HK1-sa, demonstrated the specific proteolytic removal of an amino-terminal domain, resulting in a protein product identical to HK1-SC. Such processing might constitute a regulatory mechanism governing the spatial and/or temporal expression of the protein. PMID: [10567428] 

6. Metazoans employ reversible tyrosine phosphorylation to regulate innumerable biological processes. Thus, the large-scale identification of tyrosine phosphorylation sites from primary tissues is an essential step toward a molecular systems understanding of dynamic regulation in vivo. The relative paucity of phosphotyrosine has greatly limited its identification in large-scale phosphoproteomic experiments. However, using antiphosphotyrosine peptide immunoprecipitations, we report the largest study to date of tyrosine phosphorylation sites from primary tissue, identifying 414 unique tyrosine phosphorylation sites from murine brain. To measure the conservation of phosphorylated tyrosines and their surrounding residues, we constructed a computational pipeline and identified patterns of conservation within the signature of phosphotyrosine. PMID: [18034455] 

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Function
 
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Subcellular Location
Isoform HK1-SC: Membrane. Note=Isoform HK1-SC is an integral membrane protein. 
Tissue Specificity
In rapidly growing tumor cells exhibiting highglucose catabolic rates, isoform HK1 is markedly elevated. IsoformHK1-SA, isoform HK1-SB and isoform HK1-SC are found only inspermatogenic cells. Isoform HK1-SC is detected in roundspermatids, condensing spermatids and mature sperm where it isfound in the head membranes, mitochondria of the midpiece and thefibrous sheath of the flagellum. 
Gene Ontology
GO IDGO termEvidence
GO:0005829 C:cytosol IDA:MGI.
GO:0045121 C:membrane raft IDA:MGI.
GO:0005741 C:mitochondrial outer membrane IEA:UniProtKB-SubCell.
GO:0005739 C:mitochondrion IDA:MGI.
GO:0005634 C:nucleus IEA:Compara.
GO:0005524 F:ATP binding IEA:UniProtKB-KW.
GO:0004396 F:hexokinase activity IDA:MGI.
GO:0006096 P:glycolysis TAS:MGI.
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Interpro
IPR001312;    Hexokinase.
IPR022673;    Hexokinase_C.
IPR019807;    Hexokinase_CS.
IPR022672;    Hexokinase_N.
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Pfam
PF00349;    Hexokinase_1;    2.
PF03727;    Hexokinase_2;    2.
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SMART
PROSITE
PS00378;    HEXOKINASES;    2.
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PRINTS
PR00475;    HEXOKINASE.;   
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Created Date
18-Oct-2012 
Record Type
GAS predicted 
Sequence Annotation
CHAIN         1    974       Hexokinase-1.
                             /FTId=PRO_0000013399.
NP_BIND     140    145       ATP 1 (Potential).
NP_BIND     481    482       ATP 1 (By similarity).
NP_BIND     588    593       ATP 2 (By similarity).
NP_BIND     803    804       ATP 2 (By similarity).
NP_BIND     840    844       ATP 2 (By similarity).
NP_BIND     919    923       ATP 2 (By similarity).
REGION        1     52       Hydrophobic.
REGION       53    531       Regulatory.
REGION      140    144       Glucose-6-phosphate 1 binding (By
                             similarity).
REGION      228    229       Substrate 1 binding (By similarity).
REGION      264    265       Substrate 1 binding (By similarity).
REGION      347    350       Substrate 1 binding (By similarity).
REGION      469    471       Glucose-6-phosphate 1 binding (By
                             similarity).
REGION      532    974       Catalytic.
REGION      588    592       Glucose-6-phosphate 2 binding (By
                             similarity).
REGION      659    660       Substrate 2 binding (By similarity).
REGION      676    677       Substrate 2 binding (By similarity).
REGION      712    713       Substrate 2 binding (By similarity).
REGION      917    919       Glucose-6-phosphate 2 binding (By
                             similarity).
BINDING      86     86       ATP 1 (By similarity).
BINDING     211    211       Substrate 1 (By similarity).
BINDING     265    265       Glucose-6-phosphate 1 (By similarity).
BINDING     288    288       Glucose-6-phosphate 1 (By similarity).
BINDING     291    291       Substrate 1 (By similarity).
BINDING     316    316       Substrate 1 (By similarity).
BINDING     505    505       Glucose-6-phosphate 1 (By similarity).
BINDING     659    659       Glucose-6-phosphate 2 (By similarity).
BINDING     713    713       Glucose-6-phosphate 2 (By similarity).
BINDING     736    736       ATP 2 (By similarity).
BINDING     736    736       Glucose-6-phosphate 2 (By similarity).
BINDING     739    739       Substrate 2 (By similarity).
BINDING     764    764       Substrate 2 (By similarity).
BINDING     798    798       Substrate 2 (By similarity).
BINDING     953    953       Glucose-6-phosphate 2 (By similarity).
MOD_RES      83     83       Phosphotyrosine.
VAR_SEQ       1     76       MGWGAPLLSRMLHGPGQAGETSPVPERQSGSENPASEDRRP
                             LEKQCSHHLYTMGQNCQRGQAVDVEPKIRPPLTEE -> MI
                             AAQLLAYYFTELKDDQVK (in isoform HK1).
                             /FTId=VSP_007327.
VAR_SEQ       1     52       Missing (in isoform HK1-SB and isoform
                             HK1-SC).
                             /FTId=VSP_018747.
VAR_SEQ     400    400       T -> TGWELSPDRRWYQAYMRCTQDTHR (in isoform
                             HK1-SB).
                             /FTId=VSP_007328.
MUTAGEN      67     67       P->A: Disrupts targeting to membrane;
                             when associated with N-68; Q-70; P-73; A-
                             74 and Q-75.
MUTAGEN      68     68       K->N: Disrupts targeting to membrane;
                             when associated with A-67; Q-70; P-73; A-
                             74 and Q-75.
MUTAGEN      70     70       R->Q: Disrupts targeting to membrane;
                             when associated with A-67; N-68; P-73; A-
                             74 and Q-75.
MUTAGEN      73     73       L->P: Disrupts targeting to membrane;
                             when associated with A-67; N-68; Q-70; A-
                             74 and Q-75.
MUTAGEN      74     74       T->A: Disrupts targeting to membrane;
                             when associated with A-67; N-68; Q-70; P-
                             73 and Q-75.
MUTAGEN      75     75       E->Q: Disrupts targeting to membrane;
                             when associated with A-67; N-68; Q-70; P-
                             73 and A-74.
CONFLICT    870    870       D -> S (in Ref. 1; AAA37804).
CONFLICT    899    899       E -> Q (in Ref. 2; AAB57759).
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Nucleotide Sequence
Length: 4198 bp   Go to nucleotide: FASTA
Protein Sequence
Length: 974 bp   Go to amino acid: FASTA
The verified Protein-Protein interaction information
UniProt
 Gene Symbol Ref Databases
YwhabIntAct 
Other Protein-Protein interaction resources
String database  
View Microarray data
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