Metallochaperones

Last updated

Metallochaperones are a distinct class of molecular chaperones that facilitate the intracellular transport of metal ions to metalloproteins, e.g. metalloenzymes, in cells through specific protein-protein interactions. [1] In this way, the proteins ensure that the correct metal ion cofactor is acquired by its corresponding metalloenzyme. [2] Metallochaperones are essential to the proper functioning of cells, playing a vital role in a large number of biological processes including, for example, respiration, photosynthesis, neurotransmission, and protein folding. [3]

Prior to the discovery of metallochaperones in the late 1990s, biologists believed that metal ions freely diffused within cells without the aid of auxiliary proteins. [2] Today, it is well established that these molecules contribute to the intracellular homeostatic control of biometal ions. [3]

Related Research Articles

<span class="mw-page-title-main">Ion channel</span> Pore-forming membrane protein

Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. Their functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ions across the cell membrane, controlling the flow of ions across secretory and epithelial cells, and regulating cell volume. Ion channels are present in the membranes of all cells. Ion channels are one of the two classes of ionophoric proteins, the other being ion transporters.

<span class="mw-page-title-main">Cytoskeleton</span> Network of filamentous proteins that forms the internal framework of cells

The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms. It is composed of three main components: microfilaments, intermediate filaments, and microtubules, and these are all capable of rapid growth or disassembly depending on the cell's requirements.

<span class="mw-page-title-main">Sodium–potassium pump</span> Enzyme found in the membrane of all animal cells

The sodium–potassium pump is an enzyme found in the membrane of all animal cells. It performs several functions in cell physiology.

<span class="mw-page-title-main">Metalloprotein</span> Protein that contains a metal ion cofactor

Metalloprotein is a generic term for a protein that contains a metal ion cofactor. A large proportion of all proteins are part of this category. For instance, at least 1000 human proteins contain zinc-binding protein domains although there may be up to 3000 human zinc metalloproteins.

<span class="mw-page-title-main">Calmodulin</span> Messenger protein

Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the binding of Ca2+ is required for the activation of calmodulin. Once bound to Ca2+, calmodulin acts as part of a calcium signal transduction pathway by modifying its interactions with various target proteins such as kinases or phosphatases.

<span class="mw-page-title-main">Calcium in biology</span> Use of calcium by organisms

Calcium ions (Ca2+) contribute to the physiology and biochemistry of organisms' cells. They play an important role in signal transduction pathways, where they act as a second messenger, in neurotransmitter release from neurons, in contraction of all muscle cell types, and in fertilization. Many enzymes require calcium ions as a cofactor, including several of the coagulation factors. Extracellular calcium is also important for maintaining the potential difference across excitable cell membranes, as well as proper bone formation.

Bioinorganic chemistry is a field that examines the role of metals in biology. Bioinorganic chemistry includes the study of both natural phenomena such as the behavior of metalloproteins as well as artificially introduced metals, including those that are non-essential, in medicine and toxicology. Many biological processes such as respiration depend upon molecules that fall within the realm of inorganic chemistry. The discipline also includes the study of inorganic models or mimics that imitate the behaviour of metalloproteins.

Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers. Second messengers trigger physiological changes at cellular level such as proliferation, differentiation, migration, survival, apoptosis and depolarization.

Deoxyribozymes, also called DNA enzymes, DNAzymes, or catalytic DNA, are DNA oligonucleotides that are capable of performing a specific chemical reaction, often but not always catalytic. This is similar to the action of other biological enzymes, such as proteins or ribozymes . However, in contrast to the abundance of protein enzymes in biological systems and the discovery of biological ribozymes in the 1980s, there is only little evidence for naturally occurring deoxyribozymes. Deoxyribozymes should not be confused with DNA aptamers which are oligonucleotides that selectively bind a target ligand, but do not catalyze a subsequent chemical reaction.

<span class="mw-page-title-main">Electrochemical gradient</span> Gradient of electrochemical potential, usually for an ion that can move across a membrane

An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts:

In biology, cell signaling is the process by which a cell interacts with itself, other cells, and the environment. Cell signaling is a fundamental property of all cellular life in prokaryotes and eukaryotes.

QPNC-PAGE, or QuantitativePreparativeNativeContinuousPolyacrylamideGel Electrophoresis, is a bioanalytical, one-dimensional, high-resolution and high-precision electrophoresis technique applied in biochemistry and bioinorganic chemistry to separate proteins quantitatively by isoelectric point and by continuous elution from a gel column.

<span class="mw-page-title-main">Iron in biology</span> Use of Iron by organisms

Iron is an important biological element. It is used in both the ubiquitous iron-sulfur proteins and in vertebrates it is used in hemoglobin which is essential for blood and oxygen transport.

<span class="mw-page-title-main">Phospholipase C</span> Class of enzymes

Phospholipase C (PLC) is a class of membrane-associated enzymes that cleave phospholipids just before the phosphate group (see figure). It is most commonly taken to be synonymous with the human forms of this enzyme, which play an important role in eukaryotic cell physiology, in particular signal transduction pathways. Phospholipase C's role in signal transduction is its cleavage of phosphatidylinositol 4,5-bisphosphate (PIP2) into diacyl glycerol (DAG) and inositol 1,4,5-trisphosphate (IP3), which serve as second messengers. Activators of each PLC vary, but typically include heterotrimeric G protein subunits, protein tyrosine kinases, small G proteins, Ca2+, and phospholipids.

<span class="mw-page-title-main">ATOX1</span> Protein-coding gene in the species Homo sapiens

ATOX1 is a copper metallochaperone protein that is encoded by the ATOX1 gene in humans. In mammals, ATOX1 plays a key role in copper homeostasis as it delivers copper from the cytosol to transporters ATP7A and ATP7B. Homologous proteins are found in a wide variety of eukaryotes, including Saccharomyces cerevisiae as ATX1, and all contain a conserved metal binding domain.

<span class="mw-page-title-main">Cell surface receptor</span> Class of ligand activated receptors localized in surface of plama cell membrane

Cell surface receptors are receptors that are embedded in the plasma membrane of cells. They act in cell signaling by receiving extracellular molecules. They are specialized integral membrane proteins that allow communication between the cell and the extracellular space. The extracellular molecules may be hormones, neurotransmitters, cytokines, growth factors, cell adhesion molecules, or nutrients; they react with the receptor to induce changes in the metabolism and activity of a cell. In the process of signal transduction, ligand binding affects a cascading chemical change through the cell membrane.

Amy C. Rosenzweig is a professor of Chemistry and Molecular Biosciences at Northwestern University. She was born in 1967 in Pittsburgh, Pennsylvania. Her current research interests include structural biology and bioinorganic chemistry, metal uptake and transport, oxygen activation by metalloenzymes, and characterization of membrane protein. For her work, she has been recognized by a number of national and international awards, including the MacArthur "Genius" Award in 2003.

Cation diffusion facilitators (CDFs) are transmembrane proteins that provide tolerance of cells to divalent metal ions, such as cadmium, zinc, and cobalt. These proteins are considered to be efflux pumps that remove these divalent metal ions from cells. However, some members of the CDF superfamily are implicated in ion uptake. All members of the CDF family possess six putative transmembrane spanners with strongest conservation in the four N-terminal spanners. The Cation Diffusion Facilitator (CDF) Superfamily includes the following families:

The nik operon is an operon required for uptake of nickel ions into the cell. It is present in many bacteria, but has been extensively studied in Helicobacter pylori. Nickel is an essential nutrient for many microorganisms, where it participates in a variety of cellular processes. However, excessive levels of nickel ions in cell can be fatal to the cell. Nickel ion concentration in the cell is regulated through the nik operon.

Sabeeha Sabanali Merchant is a professor of plant biology at the University of California, Berkeley. She studies the photosynthetic metabolism and metalloenzymes In 2010 Merchant led the team that sequenced the Chlamydomonas genome. She was elected a member of the National Academy of Sciences in 2012.

References

  1. Rosenzweig, Amy C (2002-06-01). "Metallochaperones: Bind and Deliver". Chemistry & Biology. 9 (6): 673–677. doi: 10.1016/S1074-5521(02)00156-4 . ISSN   1074-5521.
  2. 1 2 Finney LA, O'Halloran TV (2003-05-09). "Transition metal speciation in the cell: insights from the chemistry of metal ion receptors". Science. 300 (5621): 931–6. Bibcode:2003Sci...300..931F. doi:10.1126/science.1085049. PMID   12738850. S2CID   14863354.
  3. 1 2 Sekhon, Bhupinder Singh (2010-05-01). "Metallochaperones - an Overview". Current Chemical Biology. Retrieved 2019-01-21.