Dmitrij Tentler, Senior Researcher, Laboratory of Molecular Pharmacology; Department of Cell Cultures, Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, Russia
1994 MS Biology/Genetics St. Petersburg State University, Russia; 2001 Ph.D. Medical Genetics
Uppsala University, Sweden
Extracellular matrix (ECM) is an important element of cell micro-environment, which controls stem cell proliferation, survival and differentiation. Extracellular matrix proteins activate membrane receptors, which trigger signal transduction pathways, and change expression of certain genes. One of the first cellular responses to ECM is reorganisation of the actin cytoskeleton. A number of published studies suggest that actin cytoskeleton dynamics and redistribution of actin binding proteins modulate activity of transcription factors. However, only scanty information is available of direct mechanisms realising regulatory functions of cytoskeletal proteins.
Our research is aimed at elucidation of the role of actin-binding protein alpha-actinin 4 (Actn4) in cell type-specific gene expression in response to ECM. Actn4 is a ubiquitously expressed protein located in focal adhesion contacts, the actin cytoskeleton structures and cell nucleus. Mutations in Actn4 in human are associated with segmental glomerulosclerosis and cancerogenesis. Primarily, Actn4 was found to participate in cytoskeleton organisation, cell adhesion, and cell motility. Nuclear functions of Actn4 are yet to be uncovered. Our data suggest that Actn4 may be an important member of signal cascades mediated by ECM.
To achieve our goal, the following strategies are applied:
(i). Identification of signals that mediate intracellular localisation of Actn4.
No obvious nuclear localisation signal is present in the Actn4 molecule. The deletion analysis is applied to reveal sequences that define its translocation into cell nucleus.
(ii). Identification of the proteins, interacting with nuclear Actn4 and to assessment of their importance for functioning of the Actn4-containing complexes.
Actn4 has a number of protein partners besides actin. Interaction of Actn4 with RelA/p65 subunit of NF-kappaB and hnRNP protein family has been described in our previous papers. These data suggest its involvement in transcription and mRNA metabolism. A structure-function analysis of the Actn4 protein is ongoing to evaluate its role in gene expression control. In addition, effects of different ECM proteins on the protein composition of Actn4 complexes are to be examined.
(iii). Analysis of the effect of Actn4 on signal transduction and gene expression.
Actn4 is known to be involved in NF-kappaB dependent transcription. A significance of Actn4 interaction with different NF-kappaB sub-units for activation/repression of target genes is a subject of our studies.
Laporte J, Blondeau F, Buj-Bello A, Tentler D, Kretz C, Dahl N, Mandel JL.Characterization of the myotubularin dual specificity phosphatase gene family from yeast to human. Hum Mol Genet. 1998. 7:1703-12.
Gustavsson P, Garelli E, Draptchinskaia N, Ball S, Willig TN, Tentler D, Dianzani I, Punnett HH, Shafer FE, Cario H, Ramenghi U, Glomstein A, Pfeiffer RA, Goringe A, Olivieri NF, Smibert E, Tchernia G, Elinder G, Dahl N. Identification of microdeletions spanning the Diamond-Blackfan anemia locus on 19q13 and evidence for genetic heterogeneity. Am J Hum Genet. 1998. 63:1388-95.
Tentler D, Gustavsson P, Leisti J, Schueler M, Chelly J, Timonen E, Anneren G, Willard HF, Dahl N. Deletion including the oligophrenin-1 gene associated with enlarged cerebral ventricles, cerebellar hypoplasia, seizures and ataxia. Eur J Hum Genet. 1999. 7:541-8.
Draptchinskaia N, Gustavsson P, Andersson B, Pettersson M, Willig TN, Dianzani I, Ball S, Tchernia G, Klar J, Matsson H, Tentler D, Mohandas N, Carlsson B, Dahl N. The gene encoding ribosomal protein S19 is mutated in Diamond-Blackfan anaemia. Nat Genet. 1999. 21:169-75.
Tentler D, Gustavsson P, Elinder G, Eklof O, Gordon L, Mandel A, Dahl N. A microdeletion in 19q13.2 associated with mental retardation, skeletal malformations, and Diamond-Blackfan anaemia suggests a novel contiguous gene syndrome. J Med Genet. 2000. 37:128-31.
Schueler MG, Higgins AW, Nagaraja R, Tentler D, Dahl N, Gustashaw K, Willard HF. Large-insert clone/STS contigs in Xq11-q12, spanning deletions in patients with androgen insensitivity and mental retardation. Genomics. 2000. 66:104-9.
Tentler D, Brandberg G, Orsmark C, Betancur C, Gillberg C, Annerén G, Green ED, Carlsson B, Dahl N. A balanced reciprocal translocation t(5;7)(q14;q32) associated with autistic disorder: Molecular analysis of a chromosome 7 breakpoint. Am J Med Genet (Neuropsychiatr Genet) 2001. 105:729-36.
Prokunina L, Castillejo-Lopez C, Oberg F, Gunnarsson I, Berg L, Magnusson V, Brookes AJ, Tentler D, Kristjansdottir H, Grondal G, Bolstad AI, Svenungsson E, Lundberg I, Sturfelt G, Jonssen A, Truedsson L, Lima G, Alcocer-Varela J, Jonsson R, Gyllensten UB, Harley JB, Alarcon-Segovia D, Steinsson K, Alarcon-Riquelme ME. A regulatory polymorphism in PDCD1 is associated with susceptibility to systemic lupus erythematosus in humans. Nat Genet. 2002. 32:666-9
Tentler D, Johannesson T, Johansson M, Rastam M, Gillberg C, Orsmark C, Carlsson B, Wahlstrom J, Dahl N. A candidate region for Asperger syndrome defined by two 17p breakpoints. Eur J Hum Genet. 2003. 11:189-95.
Klar J, Gedde-Dahl T Jr, Larsson M, Pigg M, Carlsson B, Tentler D, Vahlquist A, Dahl N. Assignment of the locus for ichthyosis prematurity syndrome to chromosome 9q33.3-34.13. J Med Genet. 2004, 41:208-212.
Coppola G, Choi SH, Santos MM, Miranda CJ, Tentler D, Wexler EM, Pandolfo M, Geschwind DH. Gene expression profiling in frataxin deficient mice: Microarray evidence for significant expression changes without detectable neurodegeneration. Neurobiol Dis. 2006, 22:302-311
Bolshakova A, Petukhova O, Turoverova L, Tentler D, Babakov V, Magnusson KE, Pinaev G. Extra-cellular matrix proteins induce re-distribution of alpha-actinin-1 and alpha-actinin-4 in A431 cells. Cell Biol Int. 2007, 31(4):360-365
Abrahams BS, Tentler D, Perederiy JV, Oldham MC, Coppola G, Geschwind DH. Genome-wide analyses of human perisylvian cerebral cortical patterning. Proc Natl Acad Sci U S A. 2007, 104:17849-17854
Babakov VN, Petukhova OA, Turoverova LV, Kropacheva IV, Tentler DG, Bolshakova AV, Podolskaya EP, Magnusson KE, Pinaev GP. RelA/NF-kappaB transcription factor associates with alpha-actinin-4. Exp Cell Res. 2008, 314: 1030-1038
Khotin MG, Turoverova LV, Podol'skaia EP, Krasnov IA, Solov'eva AV, Aksenova VIu, Magnusson KE, Pinaev GP, Tentler D. Analysis of nuclear protein complexes comprising alpha-actinin-4 by 2D-electrophoresis and mass-spectrometry. Tsitologiia. 2009, 51(8): с.684-690
Turoverova LV, Khotin MG, Iudintseva NM, Magnusson KE, Blinova MI, Pinaev GP, Tentler D. Analysis of extracellular matrix proteins produced by cultured cells. Tsitologiia. 2009, 51(8): с.691-697.
Khotin M, Turoverova L, Aksenova V, Barlev N, Borutinskaite VV, Vener A, Bajenova O, Magnusson K-E, Pinaev GP and Tentler D. Proteomic analysis of ACTN4-interacting proteins reveals it’s a putative involvement in mRNA metabolism. BBRC. 2010, 397:192-196.