Roles moleculaires des proteines de choc thermique dans le fonctionnement des organismes a des temperatures normales et suite a des chocs thermiques; differents genes impliques

The heat-shock proteins

In recent years, members of the protein kinase family have been discovered at an accelerated pace. Most were first described, not through the traditional biochemical approach of protein purification and enzyme assay, but as putative protein kinase amino acid sequences deduced from the nucleotide sequences of molecularly cloned genes or complementary DNAs. Phylogenetic mapping of the conserved protein kinase catalytic domains can serve as a useful first step in the functional characterization of these newly identified family members.

http://science.sciencemag.org/content/sci/241/4861/42.full.pdf

The protein kinase family: conserved features and deduced phylogeny of the catalytic domains.

GTPases are conserved molecular switches, built according to a common structural design. Rapidly accruing knowledge of individual GTPases--crystal structures, biochemical properties, or results of molecular genetic experiments--support and generate hypotheses relating structure to function in other members of the diverse family of GTPases.

The GTPase superfamily: conserved structure and molecular mechanism

Small GTP-binding proteins (G proteins) exist in eukaryotes from yeast to human and constitute a superfamily consisting of more than 100 members. This superfamily is structurally classified into at least five families: the Ras, Rho, Rab, Sar1/Arf, and Ran families. They regulate a wide variety of cell functions as biological timers (biotimers) that initiate and terminate specific cell functions and determine the periods of time for the continuation of the specific cell functions. They furthermore play key roles in not only temporal but also spatial determination of specific cell functions. The Ras family regulates gene expression, the Rho family regulates cytoskeletal reorganization and gene expression, the Rab and Sar1/Arf families regulate vesicle trafficking, and the Ran family regulates nucleocytoplasmic transport and microtubule organization. Many upstream regulators and downstream effectors of small G proteins have been isolated, and their modes of activation and action have gradually been elucidated. Cascades and cross-talks of small G proteins have also been clarified. In this review, functions of small G proteins and their modes of activation and action are described.

Small GTP-Binding Proteins

Src family protein tyrosine kinases are activated following engagement of many different classes of cellular receptors and participate in signaling pathways that control a diverse spectrum of receptor-induced biological activities. While several of these kinases have evolved to play distinct roles in specific receptor pathways, there is considerable redundancy in the functions of these kinases, both with respect to the receptor pathways that activate these kinases and the downstream effectors that mediate their biological activities. This chapter reviews the evidence implicating Src family kinases in specific receptor pathways and describes the mechanisms leading to their activation, the targets that interact with these kinases, and the biological events that they regulate.

Cellular functions regulated by src family kinases

https://www.cell.com/cell/pdf/0092-8674(87)90223-6.pdf

Three different genes in S. cerevisiae encode the catalytic subunits of the cAMP-dependent protein kinase

We have cloned a gene (BCY1) from the yeast Saccharomyces cerevisiae that encodes a regulatory subunit of the cyclic AMP-dependent protein kinase. The encoded protein has a structural organization similar to that of the RI and RII regulatory subunits of the mammalian cyclic AMP-dependent protein kinase. Strains of S. cerevisiae with disrupted BCY1 genes do not display a cyclic AMP-dependent protein kinase in vitro, fail to grow on many carbon sources, and are exquisitely sensitive to heat shock and starvation.

Cloning and characterization of BCY1, a locus encoding a regulatory subunit of the cyclic AMP-dependent protein kinase in Saccharomyces cerevisiae.

https://www.cell.com/cell/pdf/0092-8674(87)90076-6.pdf

The S. cerevisiae CDC25 gene product regulates the RAS/adenylate cyclase pathway

https://www.cell.com/cell/pdf/0092-8674(88)90572-7.pdf

cAMP-independent control of sporulation, glycogen metabolism, and heat shock resistance in S. cerevisiae

A cDNA clone for a type II regulatory (R) subunit of the cAMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) was isolated from a rat skeletal muscle library using a specific 47-base oligonucleotide probe. The rat cDNA was 1.2 kilobases (kb) in length and contained an open reading frame of 1.113 kb representing 92% of the coding region of the molecule. Nick-translated rat cDNA was then used to isolate a mouse RII cDNA clone from a brain library that contained an open reading frame of 1.143 kb. Because both cDNAs lacked complete coding sequences, the remainder of the RII coding region was obtained from a 15-kb mouse genomic clone. The mouse RII coding region contains 1.2 kb corresponding to a 400-amino acid protein of 51.141 kDa. The mouse cDNA hybridizes to two mRNA species, a 2.4-kb form that was only observed in testis and a 6.0-kb form found in a wide range of tissues, including testis.

Mark J. Zoller

Papers

Three different genes in S. cerevisiae encode the catalytic subunits of the cAMP-dependent protein kinase

Cloning and characterization of BCY1, a locus encoding a regulatory subunit of the cyclic AMP-dependent protein kinase in Saccharomyces cerevisiae.

The S. cerevisiae CDC25 gene product regulates the RAS/adenylate cyclase pathway

cAMP-independent control of sporulation, glycogen metabolism, and heat shock resistance in S. cerevisiae

The molecular cloning of a type II regulatory subunit of the cAMP-dependent protein kinase from rat skeletal muscle and mouse brain.