Filamin C accumulation is a strong but nonspecific immunohistochemical marker of core formation in muscle.
Filamin C is the muscle isoform of a group of large actin-crosslinking proteins. On the one hand, filamin C is associated with the Z-disk of the myofibrillar apparatus and binds to myotilin; on the other hand, it interacts with the sarcoglycan complex at the sarcolemma. Filamin C may be involved in reorganizing the cytoskeleton in response to signalling events and in muscle it may, in addition, fulfill structural functions at the Z-disk. An examination of biopsies from patients with multi-minicore myopathy, central core myopathy and neurogenic target fibers with core-like target formations (TF) revealed strong reactivity of all the cores and target formations with two different anti-filamin C antibodies. In all three conditions, the immunoreactivity in the cores for filamin C was considerably stronger than that for desmin. Only for alphaB-crystallin were comparable levels of immunoreactivity detected. There was no difference in intensity for filamin C between the three pathological conditions. Thus, filamin C along with alphaB-crystallin is a strong and robust, but nonspecific marker of core formation. The reason why filamin C accumulates in cores is unclear at present, but we postulate that it may be critically involved in the chain of events eventually leading to myofibrillar degeneration.
Bönnemann
C G
CG
Division of Neurology, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, 34th Strteet and Civic Center Boulevard, Philadelphia, PA 19104, USA. bonnemann@email.chop.edu
Thompson
T G
TG
van der Ven
P F M
PF
Goebel
H H
HH
Warlo
I
I
Vollmers
B
B
Reimann
J
J
Herms
J
J
Gautel
M
M
Takada
F
F
Beggs
A H
AH
Fürst
D O
DO
Kunkel
L M
LM
Hanefeld
F
F
Schröder
R
R
D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D002352:Carrier Proteins / Q000378:metabolism; D003285:Contractile Proteins / Q000378:metabolism*; D064448:Filamins; D006801:Humans; D007150:Immunohistochemistry; D008840:Microfilament Proteins / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D018482:Muscle, Skeletal / Q000166:cytology / Q000473:pathology*; D009135:Muscular Diseases / Q000473:pathology*; D020033:Protein Isoforms / Q000378:metabolism; D012016:Reference Values
D015415:Biomarkers; D002352:Carrier Proteins; D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D020033:Protein Isoforms