The
cells
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
of
eukaryotic organisms are elaborately subdivided into functionally-distinct membrane-bound compartments. Some major constituents of eukaryotic cells are:
extracellular space,
plasma membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (t ...
,
cytoplasm,
nucleus,
mitochondria
A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...
,
Golgi apparatus,
endoplasmic reticulum
The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ( ...
(ER),
peroxisome
A peroxisome () is a membrane-bound organelle, a type of microbody, found in the cytoplasm of virtually all eukaryotic cells. Peroxisomes are oxidative organelles. Frequently, molecular oxygen serves as a co-substrate, from which hydrogen pero ...
,
vacuoles,
cytoskeleton,
nucleoplasm,
nucleolus,
nuclear matrix and
ribosome
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to ...
s.
Bacteria also have subcellular localizations that can be separated when the cell is fractionated. The most common localizations referred to include the
cytoplasm, the
cytoplasmic membrane (also referred to as the
inner membrane in
Gram-negative bacteria), the
cell wall
A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...
(which is usually thicker in
Gram-positive bacteria) and the
extracellular environment. The cytoplasm, the cytoplasmic membrane and the cell wall are subcellular localizations, whereas the extracellular environment is clearly not. Most Gram-negative bacteria also contain an
outer membrane and
periplasmic space. Unlike eukaryotes, most bacteria contain no membrane-bound organelles, however there are some exceptions (i.e.
magnetosomes).
[Schuler D. (2004). Molecular analysis of a subcellular compartment: the magnetosome membrane in Magnetospirillum gryphiswaldense.
Arch Microbiol. 181:1-7]
Protein Subcellular Location Databases
The experimentally determined subcellular locations of proteins can be found i
UniProtKBCompartments
and in a few more specialized resources, such as
the lactic acid bacterial secretome database
There are also several subcellular location databases with computational predictions, such a
the fungal secretome and subcellular proteome knowledgebase - version 2
(FunSecKB2)
the plant secretome and subcellular proteome knowledgebase
(PlantSecKB)
MetazSecKB
for protein subcellular locations of human and animals, an
ProtSecKB
for protein subcellular locations of all protists.
See also
* Protein targeting
:''This article deals with protein targeting in eukaryotes unless specified otherwise.''
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to their appropriate destinations within or outside the ce ...
* Protein subcellular localization prediction.
References
{{Reflist
Cell biology