WordNet

an inactive substance that is a vehicle for a radioactive tracer of the same substance and that assists in its recovery after some chemical reaction
(genetics) an organism that possesses a recessive gene whose effect is masked by a dominant allele; the associated trait is not apparent but can be passed on to offspring
a rack attached to a vehicle; for carrying luggage or skis or the like
a self-propelled wheeled vehicle designed specifically to carry something; "refrigerated carriers have revolutionized the grocery business"
someone whose employment involves carrying something; "the bonds were transmitted by carrier" (同)bearer, toter
a person or firm in the business of transporting people or goods or messages (同)common_carrier
(medicine) a person (or animal) who has some pathogen to which he is immune but who can pass it on to others (同)immune carrier
a boy who delivers newspapers (同)newsboy
move something or somebody around; usually over long distances
an exchange of molecules (and their kinetic energy and momentum) across the boundary between adjacent layers of a fluid or across cell membranes
move while supporting, either in a vehicle or in ones hands or on ones body; "You must carry your camping gear"; "carry the suitcases to the car"; "This train is carrying nuclear waste"; "These pipes carry waste water into the river" (同)carry
transport commercially (同)send, ship
occupy an intermediate or middle position or form a connecting link or stage between two others; "mediate between the old and the new"
acting through or dependent on an intervening agency; "the disease spread by mediate as well as direct contact"
acting or brought about through an intervening agency; "the mediated settlement brought satisfaction to both sides"

PrepTutorEJDIC

『運搬する人』;輸送業者(会社) / 運搬する物,運客車;運客設備 / (…の)媒介体,保菌者《+『of』+『名』》 / (また『aircraft carrier』)航空母艦 / (自転車・車の)荷台
(ある場所からある場所へ)…‘を'『輸送する』,運搬する《+名+from+名+to+名》 / 《文》《受動態で》(…で)…‘を'夢中にする,有頂天にする《+名+with+名》 / 〈罪人〉‘を'流刑にする / 〈U〉輸送,運送,輸送(交通)機関(transportation) / 〈C〉(軍隊や軍需品を運ぶ)輸送船,輸送機
〈紛争・相違点など〉‘を'調停する,仲裁する / 〈妥協・和解・同意など〉‘を'仲裁して成立させる / (両者の)調停をする《+『between』+『名』》 / 仲介者(媒介物)を通じての,間接の

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/02/04 02:57:12」(JST)

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A membrane transport protein (or simply transporter) is a membrane protein^[1] involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane. Transport proteins are integral transmembrane proteins; that is they exist permanently within and span the membrane across which they transport substances. The proteins may assist in the movement of substances by facilitated diffusion or active transport. These mechanisms of action are known as carrier-mediated transport.^[2]

Difference between protein channels and protein carriersEdit

Cavity in a carrier protein is not open simultaneously to the both environment (extracellular and intracellular). Either its inner gate is open, or outer gate is open, Carrier has binding sites, but porins and channel proteins have not. When a channel is opened, thousands to millions of ions can pass through the membrane in one time, but only one or a small amount of molecules can pass through a carrier molecule.

TypesEdit

Facilitated diffusion

(Grouped by Transporter Classification database categories)

1: Channels/poresEdit

α-helical protein channels such as voltage-gated ion channel (VIC), ligand-gated ion channels(LGICs)
β-barrel porins such as aquaporin
channel-forming toxins, including colicins, diphtheria toxin, and others
Nonribosomally synthesized channels such as gramicidin
Holins; which function in export of enzymes that digest bacterial cell walls in an early step of cell lysis.

Facilitated diffusion occurs in and out of the cell membrane via channels/pores and carriers/porters.

Note:

Channels:

Channels are either in open state or closed state. When a channel is opened with a slight conformational switch, it is open to both environment simultaneously (extracellular and intracellular)

Pores:

Pores are continuously open to these both environment, because they do not undergo conformational changes. They are always open and active.

2: Electrochemical potential-driven transportersEdit

2.A: Porters ( uniporters, symporters, antiporters)
- Glucose transporter
- Monoamine transporters, including:
  - Dopamine transporter (DAT)
  - Norepinephrine transporter (NET)
  - Serotonin transporter (SERT)
  - Vesicular monoamine transporters (VMAT)
- Adenine nucleotide translocator (ANT)
2.B: Nonribosomally synthesized porters, such as
- The Nigericin (Nigericin) Family
- The Ionomycin (Ionomycin) Family
2.C: Ion-gradient-driven energizers

3: Primary active transportersEdit

3.A: P-P-bond-hydrolysis-driven transporters :
- ATP-binding cassette transporter (ABC transporter), such as MDR^{[disambiguation needed]}, CFTR
- V-type ATPase ; ( "V" related to vacuolar ).
- P-type ATPase ; ( "P" related to phosphorylation), such as :
  - Na⁺/K⁺-ATPase
  - Plasma membrane Ca²⁺ ATPase
  - Proton pump
- F-type ATPase; ("F" related to factor), including: mitochondrial ATP synthase, chloroplast ATP synthase1
3.B: Decarboxylation-driven transporters
3.C: Methyltransfer-driven transporters
3.D: Oxidoreduction-driven transporters
3.E: Light absorption-driven transporters, such as rhodopsin

4: Group translocatorsEdit

The group translocators provide a special mechanism for the phosphorylation of sugars as they are transported into bacteria (PEP group translocation)

5: Electron carriersEdit

The transmembrane electron transfer carriers in the membrane include two-electron carriers, such as the disulfide bond oxidoreductases (DsbB and DsbD in E. coli) as well as one-electron carriers such as NADPH oxidase. Often these redox proteins are not considered transport proteins.

ReferencesEdit

^ Membrane transport proteins at the US National Library of Medicine Medical Subject Headings (MeSH)
^ Carrier mediated transport, Answers.com

External linksEdit

"Transport protein" at Dorland's Medical Dictionary

DDI Regulatory Guidance Request a guide to drug-drug interaction regulatory recommendations.

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