Taxonomic distribution of proteins containing DUF3635 domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing DUF3635 domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Structure, function and evolution of haspin and haspin-related proteins, adistinctive group of eukaryotic protein kinases.

Higgins JM
Cell Mol Life Sci. 2003; 60: 446-62

The haspins constitute a newly defined protein family containing a distinctiveC-terminal eukaryotic protein kinase domain and divergent N termini. Haspinhomologues are found in animals, plants and fungi, suggesting an origin early in eukaryotic evolution. Most species have a single haspin homologue. However,Saccharomyces cerevisiae has two such genes, while Caenorhabditis elegans has at least three haspin homologues and approximately 16 haspin-related genes.Mammalian haspin genes have features of retrogenes and are strongly expressed in male germ cells and at lower levels in some somatic tissues. They encode nuclear proteins with serine/threonine kinase activity. Murine haspin is reported toinhibit cell cycle progression in cell lines. One of the S. cerevisiaehomologues, ALK1, is a member of the CLB2 gene cluster that peaks in expressionat M phase and thus may function in mitosis. Therefore, the haspins are anintriguing group of kinases likely to have important roles during or followingboth meiosis and mitosis.

Identification and characterization of a haploid germ cell-specific nuclearprotein kinase (Haspin) in spermatid nuclei and its effects on somatic cells.

Tanaka H, Yoshimura Y, Nozaki M, Yomogida K, Tsuchida J, Tosaka Y, Habu T, Nakanishi T, Okada M, Nojima H, Nishimune Y
J Biol Chem. 1999; 274: 17049-57

We have cloned the entire coding region of a mouse germ cell-specific cDNAencoding a unique protein kinase whose catalytic domain contains only threeconsensus subdomains (I-III) instead of the normal 12. The protein possessesintrinsic Ser/Thr kinase activity and is exclusively expressed in haploid germcells, localizing only in their nuclei, and was thus named Haspin (for haploidgerm cell-specific nuclear protein kinase). Western blot analysis showed thatspecific antibodies recognized a protein of Mr 83,000 in the testis. Ectopically expressed Haspin was detected exclusively in the nuclei of cultured somaticcells. Even in the absence of kinase activity, however, Haspin caused cell cycle arrest at G1, resulting in growth arrest of the transfected somatic cells. In aDNA binding experiment, approximately one-half of wild-type Haspin was able tobind to a DNA-cellulose column, whereas the other half was not. In contrast, all of the deletion mutant Haspin that lacked autophosphorylation bound to the DNAcolumn. Thus, the DNA-binding activity of Haspin may, in some way, be associated with its kinase activity. These observations suggest that Haspin has somecritical roles in cell cycle cessation and differentiation of haploid germ cells.