Forisome
Forisomes are proteins occurring in the sieve tubes of Fabaceae. Their molecules are about 1-3 µm wide and 10-30 µm long. They expand and contract anisotropically in response to changes of electric field, pH, or concentration of Ca2+ ions. Unlike most other moving proteins, the change is not dependent on ATP.

Forisomes function as valves in sieve tubes of the phloem system, by reversibly changing shape between low-volume ordered crystalloid spindles and high-volume disordered spherical conformations. The change from ordered to disordered conformation involves tripling of the protein's volume, loss of birefringence present in the crystalline phase, 120% radial expansion and 30% longitudinal shrinkage. In "Vicia" it was shown that forisomes are associated to the endoplasmic reticulum at sieve plates. There are evidences that the forisomes's behavior could depend on Ca2+ changes provoked by Ca2+-permeable ion channels, located on the endoplasmic reticulum and plasma membrane of sieve elements. responsible for shape changes.

Forisomes have possible applications as biomimetic smart materials (e.g. valves in microdevices) or smart composite materials.
Q44448
Fabaceae
Concept
Q466686
anisotropically
Concept
Q46221
electric field
Concept
Q40936
pH
Concept
Q706
Ca2+
Concept
Q8054
protein
Concept
Q80863
ATP
Concept
Q2359239
sieve tubes
Concept
Q185138
phloem
Concept
Q43533
crystal
Concept
Q735188
conformations
Concept
Q108779
birefringence
Concept
Q147337
Vicia
Concept
Q79927
endoplasmic reticulum
Concept
Q2359239
sieve plates
Concept
Q706
Ca2+
Concept
Q62536
ion channels
Concept
Q79927
endoplasmic reticulum
Concept
Q29548
plasma membrane
Concept
Q2359239
sieve elements
Concept
Q1145644
biomimetic
Concept
Q1474679
smart material
Concept
Q181790
composite material
Concept
Q1437323
Forisome
Concept
Q1437323
Forisome
Concept
Q1437323
Forisome
Concept
+1^^http://www.w3.org/2001/XMLSchema#decimal
1
NUMBER
-3^^http://www.w3.org/2001/XMLSchema#decimal
-3
NUMBER
+10^^http://www.w3.org/2001/XMLSchema#decimal
10
NUMBER
-30^^http://www.w3.org/2001/XMLSchema#decimal
-30
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+30^^http://www.w3.org/2001/XMLSchema#decimal
30
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
found in taxon
part of
part of
part of