Protein complexes

thumb|280px|3D rendering of centrioles showing the triplets

A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores (zoospores), and from a wide range of microorganisms to provide motility. Many protists with flagella are known as flagellates.

complex that catalyzes the phosphorylation of ADP to ATP, during oxidative phosphorylation

thumb|right|Schematic of a cytomegalovirus

thumb|right|Cartoon representation of a proteasome. Its active sites are sheltered inside the tube (blue). The caps (red; in this case, 11S regulatory particles) on the ends regulate entry into the destruction chamber, where the protein is degraded. thumb|right|Top view of the proteasome above. Proteasomes are essential protein complexes responsible for the degradation of proteins by proteolysis, a chemical reaction that breaks peptide bonds. Enzymes that help such reactions are called proteases. Proteasomes are found inside all eukaryotes and archaea, and in some bacteria. In eukaryotes, prot

A myofibril (also known as a muscle fibril or sarcostyle) is a basic rod-like organelle of a muscle cell. Skeletal muscles are composed of long, tubular cells known as muscle fibers, and these cells contain many chains of myofibrils. Each myofibril has a diameter of 1–2 micrometres. They are created during embryonic development in a process known as myogenesis.

A spliceosome is a large ribonucleoprotein (RNP) complex found primarily within the nucleus of eukaryotic cells. The spliceosome is assembled from small nuclear RNAs (snRNA) and numerous proteins. Small nuclear RNA (snRNA) molecules bind to specific proteins to form a small nuclear ribonucleoprotein complex (snRNP, pronounced "snurps"), which in turn combines with other snRNPs to form a large ribonucleoprotein complex called a spliceosome. The spliceosome removes introns from a transcribed pre-mRNA, a type of primary transcript. This process is generally referred to as splicing. An analogy is

450px|thumb|Mechanism of NF-κB action. The classic "canonical" NF-κB complex is a heterodimer of p50 and RelA, as shown. NF-κB waits for activation in the cytosol, complexed with the inhibitory protein IκBα. Various extracellular signals can enter the cell via membrane receptors and activate the enzyme [[IκB kinase (IKK). IKK, in turn, phosphorylates the IκBα protein, which results in ubiquitination, dissociation of IκBα from NF-κB, and eventual degradation of IκBα by the proteasome. The activated NF-κB is then translocated into the nucleus where it binds to specific sequences of DNA called re

physical interactions and constructions between multiple proteins

multi-protein intracellular complex capable of degrading various types of RNA molecules

stable macromolecular complex

right|thumb|460px|Electron micrographs showing alpha-carboxysomes from the chemoautotrophic bacterium Halothiobacillus|Halothiobacillus neapolitanus: (A) arranged within the cell, and (B) intact upon isolation. Scale bars indicate 100 nm.

thumb|right | Diagram of an Inflammasome Inflammasomes are cytosolic multiprotein complexes of the innate immune system responsible for the activation of inflammatory responses and cell death. They are formed as a result of specific cytosolic pattern recognition receptors (PRRs), which are molecular sensors of microbe-derived pathogen-associated molecular patterns (PAMPs), damage-associated molecular patterns (DAMPs) from the host cell, or homeostatic disruptions. Activation and assembly of the inflammasome promotes the activation of caspase-1, which then proteolytically cleaves pro-inflammato

class of protein complexes, the second protein complex in photosynthetic light reactions

complex that contains 10 different types of subunits

450px|thumb|Figure 1. An interphase nucleus (left) and a set of mitotic chromosomes (right) from human tissue culture cells. Bar, 10 μm. Condensins are large protein complexes that play a central role in chromosome condensation and segregation during mitosis and meiosis (Figure 1). Their subunits were originally identified as major components of mitotic chromosomes assembled in Xenopus egg extracts.

macromolecular complex formed by two, usually non-covalently bound, macromolecules

The translocon (also called a translocator or translocation channel) is a general term for a protein channel in biological membranes that functions to move polypeptides across the membrane or insert them into the lipid bilayer. This structure is a key component of the protein translocation pathway in all organisms, from bacteria, archaea, and eukaryotes.

macromolecular complex

The degradosome is a multiprotein complex present in most bacteria that is involved in the processing of ribosomal RNA and the degradation of messenger RNA and is regulated by Non-coding RNA. It contains the proteins RNA helicase B, RNase E and Polynucleotide phosphorylase.

In molecular biology, an interactome is the whole set of molecular interactions in a particular cell. The term specifically refers to physical interactions among molecules (such as those among proteins, also known as protein–protein interactions (PPIs); or between small molecules and proteins.) but can also describe sets of indirect interactions among genes (genetic interactions). 400px|right|thumb|Part of the DISC1 interactome with genes represented by text in boxes and interactions noted by lines between the genes. From Hennah and Porteous, 2009. The word "interactome" was originally coined

multisubunit complex that is located at the replication origins of a chromosome

complex of three proteins

biological factor

GroEL is a protein which belongs to the chaperonin family of molecular chaperones, and is found in many bacteria. It is required for the proper folding of many proteins. To function properly, GroEL requires the lid-like cochaperonin protein complex GroES. In eukaryotes the organellar proteins Hsp60 and Hsp10 are structurally and functionally nearly identical to GroEL and GroES, respectively, due to their endosymbiotic origin.

protein complex that has aspartic-type endopeptidase activity, and contains a catalytic subunit, presenilin (PS), that is a prototypical member of the GxGD-type aspartyl peptidases. The complex also contains additional subunits, including nicastrin

Shelterin (also called telosome) is a protein complex known to protect telomeres in many eukaryotes from DNA repair mechanisms, as well as to regulate telomerase activity. In mammals and other vertebrates, telomeric DNA consists of repeating double-stranded 5'-TTAGGG-3' (G-strand) sequences (2-15 kilobases in humans) along with the 3'-AATCCC-5' (C-strand) complement, ending with a 50-400 nucleotide 3' (G-strand) overhang. Much of the final double-stranded portion of the telomere forms a T-loop (Telomere-loop) that is invaded by the 3' (G-strand) overhang to form a small D-l

A nanogel is a polymer-based, crosslinked hydrogel particle on the sub-micron scale. These complex networks of polymers present a unique opportunity in the field of drug delivery at the intersection of nanoparticles and hydrogel synthesis. Nanogels can be natural, synthetic, or a combination of the two and have a high degree of tunability in terms of their size, shape, surface functionalization, and degradation mechanisms. Given these inherent characteristics in addition to their biocompatibility and capacity to encapsulate small drugs and molecules, nanogels are a promising strategy to treat

Calprotectin is a complex of the mammalian proteins S100A8 and S100A9. Other names for calprotectin include MRP8-MRP14, calgranulin A and B, cystic fibrosis antigen, L1, 60BB antigen, and 27E10 antigen. The proteins exist as homodimers but preferentially exist as S100A8/A9 heterodimers or heterotetramers (calprotectin) with antimicrobial, proinflammatory and prothrombotic properties. In the presence of calcium, calprotectin is capable of sequestering the transition metals iron, manganese and zinc via chelation. This metal sequestration affords the complex antimicrobial properties. Calprotectin

protein complex that interacts with the carboxy-terminal domain of the largest subunit of RNA polymerase II

protein complex

Heat shock 10 kDa protein 1 (Hsp10), also known as chaperonin 10 (cpn10) or early-pregnancy factor (EPF), is a protein that in humans is encoded by the HSPE1 gene. The homolog in E. coli is GroES that is a chaperonin which usually works in conjunction with GroEL.

RuvABC is a complex of three proteins that mediate branch migration and resolve the Holliday junction created during homologous recombination in bacteria. As such, RuvABC is critical to bacterial DNA repair.

mTOR Complex 2 (mTORC2) is an acutely rapamycin-insensitive protein complex formed by serine/threonine kinase mTOR that regulates cell proliferation and survival, cell migration and cytoskeletal remodeling. The complex itself is rather large, consisting of seven protein subunits. The catalytic mTOR subunit, DEP domain containing mTOR-interacting protein (DEPTOR), mammalian lethal with sec-13 protein 8 (mLST8, also known as GβL), and TTI1/TEL2 complex are shared by both mTORC2 and mTORC1. Rapamycin-insensitive companion of mTOR (RICTOR), mammalian stress-activated protein kinase interacting pro

G beta Gamma complex

In biochemistry, a metabolon is a temporary structural-functional complex formed between sequential enzymes of a metabolic pathway, held together both by non-covalent interactions and by structural elements of the cell, such as integral membrane proteins and proteins of the cytoskeleton.

REDIRECT Tetrameric protein#Homotetramers and heterotetramers

inclusion bodies for misfolded proteins

REDIRECT Tetrameric protein#Homotetramers and heterotetramers

The CD79 receptor complex, also known as CD79A:CD79B or Igα:Igβ, is a heterodimeric signaling component of the B-cell receptor (BCR) complex. This transmembrane heterodimer consists of the B-cell antigen receptor complex-associated protein alpha chain (CD79A/Igα) and the B-cell antigen receptor complex-associated protein beta chain (CD79B/Igβ). The CD79 complex is expressed almost exclusively on B cells and B-cell neoplasms, making it valuable for differential diagnosis of B-cell malignancies from T-cell or myeloid neoplasms.

Trimeric protein complex that possesses endonuclease activity; involved in meiotic recombination, DNA repair and checkpoint signaling. In Saccharomyces cerevisiae, the complex comprises Mre11p, Rad50p, and Xrs2p; complexes identified in other species

class of protein complexes

protein with 4 quaternary-structure-subunits

The exocyst is an octameric protein complex involved in vesicle trafficking, specifically the tethering and spatial targeting of post-Golgi vesicles to the plasma membrane prior to vesicle fusion. It is implicated in a number of cell processes, including exocytosis, cell migration, and growth.

contractile ring, i.e. a cytoskeletal structure composed of actin filaments and myosin, that forms beneath the plasma membrane at the mother-bud neck in mitotic cells that divide by budding in preparation for completing cytokinesis. An example of t