Analysis of the protein kinome of Entamoeba histalytica

Anamika, K and Bhattacharya, A and Srinivasan, N (2008) Analysis of the protein kinome of Entamoeba histalytica. In: Proteins: Structure, Function, and Bioinformatics, 71 (2). pp. 995-1006.

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Abstract

Protein kinases play important roles in almost all major gnaling and regulatory pathways of eukaryotic organisms. Members in the family of protein kinases make up a substantial fraction of eukaryotic proteome. Analysis of the protein kinase repertoire (kinome) would help in the better understanding of the regulatory processes. In this rticle,we report the identification and analysis of the repertoire of protein kinases in the intracellular parasite Entamoeba histolytica. Using a combination of various sensitive sequence search methods and manual analysis, we have identified a set of 307 protein kinases in E. histolytica genome. We have classified these protein kinases into different subfamilies originally defined by Hanks and Hunter and studied these kinases further in the context of noncatalytic domains that are tethered to catalytic kinase domain. Compared to other eukaryotic organisms, protein kinases from E. histolytica vary in terms of their domain organization and displays features that may have a bearing in the unusual biology of this organism. Some of the parasitic kinases show high sequence similarity in the catalytic domain region with calmodulin/calcium dependent protein kinase subfamily. However, they are unlikely to act like typical calcium/calmodulin dependent kinases as they lack noncatalytic domains characteristic of such kinases in other organisms. Such kinases form the largest subfamily of kinases in E. histolytica. Interestingly, a PKA/PKG-like subfamily member is tethered to pleckstrin homology domain. Although potential cyclins and cyclindependent kinases could be identified in the genome the likely absence of other cell cycle proteins suggests unusual nature of cell cycle in E. histolytica. Some of the unusual features recognized in our analysis include the absence of MEK as a part of the Mitogen Activated Kinase signaling pathway and identification of transmembrane region containing Src kinase-like kinases. Sequences which could not be classified into known subfamilies of protein kinases have unusual domain architectures. Many such unclassified protein kinases are tethered to domains which are Cysteine-rich and to domains known to be involved in protein–protein interactions. Our kinome analysis of E. histolytica suggests that the organism possesses a complex protein phosphorylation network that involves many unusual kinases.

Item Type:	Journal Article
Publication:	Proteins: Structure, Function, and Bioinformatics
Publisher:	John Wiley & Sons
Additional Information:	Copyright of this article belongs to John Wiley & Sons.
Keywords:	Entamoeba histolytica;domain structures;protein evolution;protein kinases;protein phosphorylation;signal transduction.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	16 Sep 2008 07:37
Last Modified:	19 Sep 2010 04:49
URI:	http://eprints.iisc.ac.in/id/eprint/15751

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