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1.
Wang Y Guan X Fok KL Li S Zhang X Miao S Zong S Koide SS Chan HC Wang L 《Cellular and molecular life sciences : CMLS》2008,65(23):3822-3829
Rhomboid family members are widely conserved and found in all three kingdoms of life. They are serine proteases and serve
important regulatory functions. In the present study, a novel gene highly expressed in the testis, RHBDD1, is shown to be
a new member of the Rhomboid family, participating in the cleavage of BIK, a proapoptotic member of the Bcl-2 family. The
RHBDD1-involved proteolytic modification is upstream of the BIK protein degradation pathway. Mutagenesis studies show that
the amino acid residues glycine142 and serine144 of RHBDD1 are crucial for its activity in cleaving BIK at a site located
in the transmembrane region. Overexpression or knock-down of RHBDD1 in HEK 293T cells can reduce or enhance BIK-mediated apoptosis,
respectively. The present findings suggest that, by acting as a serine protease, RHBDD1 modulates BIK-mediated apoptotic activity.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Received 31 July 2008; received after revision 16 September 2008; accepted 19 September 2008 相似文献
2.
Improper protein folding (misfolding) can lead to the formation of disordered (amorphous) or ordered (amyloid fibril) aggregates.
The major lens protein, α-crystallin, is a member of the small heat-shock protein (sHsp) family of intracellular molecular
chaperone proteins that prevent protein aggregation. Whilst the chaperone activity of sHsps against amorphously aggregating
proteins has been well studied, its action against fibril-forming proteins has received less attention despite the presence
of sHsps in deposits found in fibril-associated diseases (e.g. Alzheimer’s and Parkinson’s). In this review, the literature
on the interaction of αB-crystallin and other sHsps with fibril-forming proteins is summarized. In particular, the ability
of sHsps to prevent fibril formation, their mechanisms of action and the possible in vivo consequences of such associations are discussed. Finally, the fibril-forming propensity of the crystallin proteins and its
implications for cataract formation are described along with the potential use of fibrillar crystallin proteins as bionanomaterials.
Received 13 June 2008; received after revision 29 July 2008; accepted 05 August 2008 相似文献
3.
The elucidation of assembly pathways of multi-subunit membrane proteins is of growing interest in structural biology. In this
study, we provide an analysis of the assembly of the asymmetrically oriented PsaC subunit on the pseudo C2-symmetric Photosystem I core. Based on a comparison of the differences in the NMR solution structure of unbound PsaC with
that of the X-ray crystal structure of bound PsaC, and on a detailed analysis of the PsaC binding site surrounding the FX iron-sulfur cluster, two models can be envisioned for what are likely the last steps in the assembly of Photosystem I. Here,
we dissect both models and attempt to address heretofore unrecognized issues by proposing a mechanism that includes a thermodynamic
perspective. Experimental strategies to verify the models are proposed. In closing, the evolutionary aspects of the assembly
process will be considered, with special reference to the structural arrangement of the PsaC binding surface.
Received 22 October 2008; received after revision 17 November 2008; accepted 05 December 2008 相似文献
4.
Reticulons (RTNs) are membrane-spanning proteins sharing a typical domain named reticulon homology domain (RHD). RTN genes
have been identified in all eukaryotic organisms examined so far, and the corresponding proteins have been found predominantly
associated to the endoplasmic reticulum membranes. In animal and yeast, in which knowledge of the protein family is more advanced,
RTNs are involved in numerous cellular processes such as apoptosis, cell division and intracellular trafficking. Up to now,
a little attention has been paid to their plant counterparts, i.e., RTNLBs. In this review, we summarize the data available for RTNLB proteins and, using the data obtained with animal and
yeast models, several functions for RTNLBs in plant cells are proposed and discussed.
Received 01 July 2008; received after revision 08 September 2008; accepted 30 September 2008 相似文献
5.
The mitochondrial PHB complex: roles in mitochondrial respiratory complex assembly, ageing and degenerative disease 总被引:16,自引:0,他引:16
Nijtmans LG Artal SM Grivell LA Coates PJ 《Cellular and molecular life sciences : CMLS》2002,59(1):143-155
Although originally identified as putative negative regulators of the cell cycle, recent studies have demonstrated that the
PHB proteins act as a chaperone in the assembly of subunits of mitochondrial respiratory chain complexes. The two PHB proteins,
Phb1p and Phb2p, are located in the mitochondrial inner membrane where they form a large complex that represents a novel type
of membrane-bound chaperone. On the basis of its native molecular weight, the PHB-complex should contain 12-14 copies of both
Phb1p and Phb2p. The PHB complex binds directly to newly synthesised mitochondrial translation products and stabilises them
against degradation by membrane-bound metalloproteases belonging to the family of mitochondrial triple-A proteins. Sequence
homology assigns Phb1p and Phb2p to a family of proteins which also contains stomatins, HflKC, flotillins and plant defence
proteins. However, to date only the bacterial HflKC proteins have been shown to possess a direct functional homology with
the PHB complex. Previously assigned actions of the PHB proteins, including roles in tumour suppression, cell cycle regulation,
immunoglobulin M receptor binding and apoptosis seem unlikely in view of any hard evidence in their support. Nevertheless,
because the proteins are probably indirectly involved in ageing and cancer, we assess their possible role in these processes.
Finally, we suggest that the original name for these proteins, the prohibitins, should be amended to reflect their roles as
proteins that hold badly formed subunits, thereby keeping the nomenclature already in use but altering its meaning to reflect
their true function more accurately.
Received 21 May 2001; received after revision 2 July 2001; accepted 24 July 2001 相似文献
6.
Y. Sugano 《Cellular and molecular life sciences : CMLS》2009,66(8):1387-1403
Dye-decolorizing peroxidase (DyP) is produced by a basidiomycete (Thanatephorus cucumeris Dec 1) and is a member of a novel heme peroxidase family (DyP-type peroxidase family) that appears to be distinct from general
peroxidases. Thus far, 80 putative members of this family have been registered in the PeroxiBase database (http://peroxibase.isbsib.ch/)
and more than 400 homologous proteins have been detected via PSI-BLAST search. Although few studies have characterized the
function and structure of these proteins, they appear to be bifunctional enzymes with hydrolase or oxygenase, as well as typical
peroxidase activities. DyP-type peroxidase family suggests an ancient root compared with other general peroxidases because
of their widespread distribution in the living world. In this review, firstly, an outline of the characteristics of DyP from
T. cucumeris is presented and then interesting characteristics of the DyP-type peroxidase family are discussed.
Received 14 October 2008; received after revision 12 November 2008; accepted 17 November 2008 相似文献
7.
Immunophilins: for the love of proteins 总被引:1,自引:0,他引:1
Barik S 《Cellular and molecular life sciences : CMLS》2006,63(24):2889-2900
Immunophilins are chaperones that may also exhibit peptidylprolyl isomerase (PPIase) activity. This review summarizes our
knowledge of the two largest families of immunophilins, namely cyclophilin and FK506-binding protein, and a novel chimeric
dual-family immunophilin, named FK506- and cyclosporin-binding protein (FCBP). The larger members of each family are modular
in nature, consisting of multiple PPIase and/or protein-protein interaction domains. Despite the apparent difference in their
sequence and three-dimensional structure, the three families encode similar enzymatic and biological functions. Recent studies
have revealed that many immunophilins possess a chaperone function independent of PPIase activity. Knockout animal studies
have confirmed multiple essential roles of immunophilins in physiology and development. An immunophilin is indeed a natural
‘protein-philin’ (Greek ‘philin’ = friend) that interacts with proteins to guide their proper folding and assembly.
Received: 7 May 2006; received after revision 3 July 2006; accepted 24 August 2006 相似文献
8.
Diverse molecular functions of Hu proteins 总被引:1,自引:1,他引:0
9.
Engen JR Wales TE Hochrein JM Meyn MA Banu Ozkan S Bahar I Smithgall TE 《Cellular and molecular life sciences : CMLS》2008,65(19):3058-3073
Src-family kinases are modular signaling proteins involved in a diverse array of cellular processes. All members of the Src
family share the same domain organization, with modular SH3, SH2 and kinase domains followed by a C-terminal negative regulatory
tail. X-ray crystallographic analyses of several Src family members have revealed critical roles for the SH3 and SH2 domains
in the down-regulation of the kinase domain. This review focuses on biological, biophysical, and computational studies that
reveal conformationally distinct active states within this unique kinase family.
Received 10 March 2008; received after revision 17 May 2008; accepted 21 May 2008 相似文献
10.
de Keyzer J van der Does C Driessen AJ 《Cellular and molecular life sciences : CMLS》2003,60(10):2034-2052
The major route of protein translocation in bacteria is the so-called general secretion pathway (Sec-pathway). This route has been extensively studied in Escherichia coli and other bacteria. The movement of preproteins across the cytoplasmic membrane is mediated by a multimeric membrane protein complex called translocase. The core of the translocase consists of a proteinaceous channel formed by an oligomeric assembly of the heterotrimeric membrane protein complex SecYEG and the peripheral adenosine triphosphatase (ATPase) SecA as molecular motor. Many secretory proteins utilize the molecular chaperone SecB for targeting and stabilization of the unfolded state prior to translocation, while most nascent inner membrane proteins are targeted to the translocase by the signal recognition particle and its membrane receptor. Translocation is driven by ATP hydrolysis and the proton motive force. In the last decade, genetic and biochemical studies have provided detailed insights into the mechanism of preprotein translocation. Recent crystallographic studies on SecA, SecB and the SecYEG complex now provide knowledge about the structural features of the translocation process. Here, we will discuss the mechanistic and structural basis of the translocation of proteins across and the integration of membrane proteins into the cytoplasmic membrane.Received 10 January 2003; received after revision 2 April 2003; accepted 4 April 2003 相似文献
11.
The BAG (Bcl-2 associated athanogene) family is a multifunctional group of proteins that perform diverse functions ranging from apoptosis to tumorigenesis.
An evolutionarily conserved group, these proteins are distinguished by a common conserved region known as the BAG domain.
BAG genes have been found in yeasts, plants, and animals, and are believed to function as adapter proteins forming complexes
with signaling molecules and molecular chaperones. In humans, a role for BAG proteins has been suggested in carcinogenesis,
HIV infection, and Parkinson’s disease. These proteins are therefore potential therapeutic targets, and their expression in
cells may serve as a predictive tool for such diseases. In plants, the Arabidopsis thaliana genome contains seven homologs of the BAG family, including four with domain organization similar to animal BAGs. Three members
contain a calmodulin-binding domain possibly reflecting differences between plant and animal programmed cell death. This review
summarizes current understanding of BAG proteins in both animals and plants.
Received 21 November 2007; received after revision 17 December 2007; accepted 2 January 2008 相似文献
12.
13.
Berger W Steiner E Grusch M Elbling L Micksche M 《Cellular and molecular life sciences : CMLS》2009,66(1):43-61
The unique and evolutionary highly conserved major vault protein (MVP) is the main component of ubiquitous, large cellular
ribonucleoparticles termed vaults. The 100 kDa MVP represents more than 70% of the vault mass which contains two additional
proteins, the vault poly (ADP-ribose) polymerase (vPARP) and the telomerase-associated protein 1 (TEP1), as well as several
short untranslated RNAs (vRNA). Vaults are almost ubiquitously expressed and, besides chemotherapy resistance, have been implicated
in the regulation of several cellular processes including transport mechanisms, signal transmissions and immune responses.
Despite a growing amount of data from diverse species and systems, the definition of precise vault functions is still highly
complex and challenging. Here we review the current knowledge on MVP and vaults with focus on regulatory functions in intracellular
signal transduction and immune defence.
Received 27 June 2008; received after revision 25 July 2008; accepted 30 July 2008 相似文献
14.
The chloroplast is the hallmark organelle of plants. It performs photosynthesis and is therefore required for photoautotrophic
plant growth. The chloroplast is the most prominent member of a family of related organelles termed plastids which are ubiquitous
in plant cells. Biogenesis of the chloroplast from undifferentiated proplastids is induced by light. The generally accepted
endosymbiont hypothesis states that chloroplasts have arisen from an internalized cyanobacterial ancestor. Although chloroplasts
have maintained remnants of the ancestral genome (plastome), the vast majority of the genes encoding chloroplast proteins
have been transferred to the nucleus. This poses two major challenges to the plant cell during chloroplast biogenesis: First,
light and developmental signals must be interpreted to coordinately express genetic information contained in two distinct
compartments. This is to ensure supply and stoichiometry of abundant chloroplast components. Second, developing chloroplasts
must efficiently import nuclear encoded and cytosolically synthesized proteins. A subset of proteins, including such encoded
by the plastome, must further be sorted to the thylakoid compartments for assembly into the photosynthetic apparatus.
Received 1 September 2000; received after revision 27 October 2000; accepted 1 November 2000 相似文献
15.
Moorwood C 《Cellular and molecular life sciences : CMLS》2008,65(19):2957-2963
Syncoilin is a member of the intermediate filament protein family, highly expressed in skeletal and cardiac muscle. Syncoilin
binds α-dystrobrevin, a component of the dystrophin associated protein complex (DAPC) located at the muscle cell membrane,
and desmin, a muscle-specific intermediate filament protein, thus providing a link between the DAPC and the muscle intermediate
filament network. This link may be important for muscle integrity and force transduction during contraction, a theory that
is supported by the reduced force-generating capacity of muscles from syncoilin-null mice. Additionally, syncoilin is found
at increased levels in the regenerating muscle fibres of patients with muscular dystrophies and mouse models of muscle disease.
Therefore, syncoilin may be important for muscle regeneration in response to injury. The aims of this article are to review
current knowledge about syncoilin and to discuss its possible functions in skeletal muscle.
Received 21 May 2008; received after revision 10 July 2008; accepted 18 July 2008 相似文献
16.
Functions of fatty acid binding proteins 总被引:1,自引:0,他引:1
R. M. Kaikaus N. M. Bass R. K. Ockner 《Cellular and molecular life sciences : CMLS》1990,46(6):617-630
Summary Cytosolic fatty acid binding proteins (FABP) belong to a gene family of which eight members have been conclusively identified. These 14–15 kDa proteins are abundantly expressed in a highly tissue-specific manner. Although the functions of the cytosolic FABP are not clearly established, they appear to enhance the transfer of long-chain fatty acids between artificial and native lipid membranes, and also to have a stimulatory effect on a number of enzymes of fatty acid metabolism in vitro. These findings, as well as the tissue expression, ligand binding properties, ontogeny and regulation of these proteins provide a considerable body of indirect evidence supporting a broad role for the FABP in the intracellular transport and metabolism of long-chain fatty acids. The available data also support the existence of structure- and tissue-specific specialization of function among different members of the FABP gene family. Moreover, FABP may also have a possible role in the modulation of cell growth and proliferation, possibly by virtue of their affinity for ligands such as prostaglandins, leukotrienes and fatty acids, which are known to influence cell growth activity. FABP structurally unrelated to the cytosolic gene family have also been identified in the plasma membranes of several tissues (FABPpm). These proteins have not been fully characterized to date, but strong evidence suggests that they function in the transport of long-chain fatty acids across the plasma membrane. 相似文献
17.
DnaJ/Hsp40 (heat shock protein 40) proteins have been preserved throughout evolution and are important for protein translation,
folding, unfolding, translocation, and degradation, primarily by stimulating the ATPase activity of chaperone proteins, Hsp70s.
Because the ATP hydrolysis is essential for the activity of Hsp70s, DnaJ/Hsp40 proteins actually determine the activity of
Hsp70s by stabilizing their interaction with substrate proteins. DnaJ/Hsp40 proteins all contain the J domain through which
they bind to Hsp70s and can be categorized into three groups, depending on the presence of other domains. Six DnaJ homologs
have been identified in Escherichia coli and 22 in Saccharomyces cerevisiae. Genome-wide analysis has revealed 41 DnaJ/Hsp40 family members (or putative members) in humans. While 34 contain the typical
J domains, 7 bear partially conserved J-like domains, but are still suggested to function as DnaJ/ Hsp40 proteins. DnaJA2b,
DnaJB1b, DnaJC2, DnaJC20, and DnaJC21 are named for the first time in this review; all other human DnaJ proteins were dubbed
according to their gene names, e.g. DnaJA1 is the human protein named after its gene DNAJA1. This review highlights the progress
in studying the domains in DnaJ/Hsp40 proteins, introduces the mechanisms by which they interact with Hsp70s, and stresses
their functional diversity.
Received 27 April 2006; received after revision 5 June 2006; accepted 19 July 2006 相似文献
18.
19.
The continuing disappearance of “pure” Ca2+ buffers 总被引:1,自引:1,他引:0
B. Schwaller 《Cellular and molecular life sciences : CMLS》2009,66(2):275-300
Advances in the understanding of a class of Ca2+-binding proteins usually referred to as “Ca2+ buffers” are reported. Proteins historically embraced within this group include parvalbumins (α and β), calbindin-D9k, calbindin-D28k
and calretinin. Within the last few years a wealth of data has accumulated that allow a better understanding of the functions
of particular family members of the >240 identified EF-hand Ca2+-binding proteins encoded by the human genome. Studies often involving transgenic animal models have revealed that they exert
their specific functions within an intricate network consisting of many proteins and cellular mechanisms involved in Ca2+ signaling and Ca2+ homeostasis, and are thus an essential part of the Ca2+ homeostasome. Recent results indicate that calbindin-D28k, possibly also calretinin and oncomodulin, the mammalian β parvalbumin,
might have additional Ca2+ sensor functions, leaving parvalbumin and calbindin-D9k as the only “pure” Ca2+ buffers.
Received 10 September 2008; received after revision 15 October 2008; accepted 4 November 2008 相似文献
20.
The Rh (Rhesus) genes encode a family of conserved proteins that share a structural fold of 12 transmembrane helices with
members of the major facilitator superfamily. Interest in this family has arisen from the discovery of Rh factor’s involvement
in hemolytic disease in the fetus and newborn, and of its homologs widely expressed in epithelial tissues. The Rh factor and
Rh-associated glycoprotein (RhAG), with epithelial cousins RhBG and RhCG, form four subgroups conferring upon vertebrates
a genealogical commonality. The past decade has heralded significant advances in understanding the phylogenetics, allelic
diversity, crystal structure, and biological function of Rh proteins. This review describes recent progress on this family
and the molecular insights gleaned from its gene evolution, membrane biology, and disease association. The focus is on its
long evolutionary history and surprising structural conservation from prokaryotes to humans, pointing to the importance of
its functional role, related to but distinct from ammonium transport proteins. 相似文献