er catalytic activity and which may therefore be pseudokinases. The HMM library has also been shown to be selective enough to classify some kinases of the ‘Other’ group of S. cerevisiae into the main ePK families. Among the ePKs, E. cuniculi was found to harbour 4 kinases of the AGC family, 5 CAMKs, 2 CK1s, 12 CMGCs, 1 TKL, and 5 kinases which, by complete clustering analysis with the kinomes of S. cerevisiae and S. pombe, were found to belong to the ‘Other’ group. E. cuniculi was also found to encode 3 atypical protein kinases: 2 of the PIKK family and one of the RIO family. Of the remaining 89 ePKs, deletion phenotypes were assessed under various stress conditions. 46% of these non-essential ePKs of fission yeast were found to exhibit hypersensitivity to at least one of the 17 stress factors tested, allowing the functional grouping of fission yeast ePKs into PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19796427 4 major signalling pathways according to the nature of the stress. We have carried out an independent database search for ePKs and aPKs in S. pombe and have identified 3 additional ePKs, one of which is the fission yeast homologue of S. cerevisiae Bud32p. Thus, the kinome of S. pombe was found to consist of 109 ePKs and 8 aPKs. Both the kinomes of S. cerevisiae and S. pombe lack kinases of the families RGC, TK, and Alpha. Phylogenetic analysis suggests that 91/109 of ePKs of fission yeast share a homologue in S. cerevisiae; likewise 96/115 of ePKs of S. cerevisiae have a homologue in S. pombe. With the inclusion of aPKs 100/117 of S. pombe kinases have homologues in S. cerevisiae. The same was found to be true for 104/124 of S. cerevisiae kinases. Therefore, the degree of homology between the kinomes of the two fungi is ~20% greater than previously reported. Part of the improvement is because the multilevel HMM library produces an automatic classification of protein kinases into families. The advantage of doing family-family comparisons, and the subsequent generation of multiple alignments and phylogenetic analysis for each family, is that proteins that are closer sequence-wise make better alignments. Since a phylogenetic tree is only as good as the underlying alignment, splitting the kinases into families prior to BAY41-2272 web generating phylogenies is a more powerful method for comparing entire kinomes. These roles may therefore be highly conserved if CAD25005.1 is genuinely functionally related to these yeast kinases. However, CAD25005.1 also has a phorbol ester/diacylglycerol-binding C1 domain that is shared with yeast protein kinase Cs, although they are located at the opposite end of the polypeptide to their position in, for example, budding yeast Pkc1p, and there is no C2 domain. CAD26208.1 is related to Chk1p/Chk1, while CAD26242.1 and CAD26452.1 are both related to Kin1p/Kin2p of budding yeast and Kin1/ Ppk25 of fission yeast. Given that budding yeast cells lacking both KIN1 and KIN2 are viable, finding two homologues of these kinases in E. cuniculi is surprising. In fission yeast, loss of just one of the two isoforms produced a significant morphological defect, so perhaps simultaneous deletion of both isoforms will reveal a more critical role for this group of kinases in fission yeast. It also remains possible that a third budding yeast CAMK may function redundantly with Kin1p 
and Kin2p. Budding yeast Kin1p and Kin2p are the homologues of C. elegans Par-1, a protein kinase essential for the establishment of anteriorposterior polarity in the onecell embryo and generally involved in t