FLNB

This gene encodes a member of the filamin family. The encoded protein interacts with glycoprotein Ib alpha as part of the process to repair vascular injuries. The platelet glycoprotein Ib complex includes glycoprotein Ib alpha, and it binds the actin cytoskeleton. Mutations in this gene have been found in several conditions: atelosteogenesis type 1 and type 3; boomerang dysplasia; autosomal dominant Larsen syndrome; and spondylocarpotarsal synostosis syndrome. Multiple alternatively spliced transcript variants that encode different protein isoforms have been described for this gene. [provided by RefSeq, Nov 2009]

Filamin B

Connects cell membrane constituents to the actin cytoskeleton. May promote orthogonal branching of actin filaments and links actin filaments to membrane glycoproteins. Anchors various transmembrane proteins to the actin cytoskeleton. Interaction with FLNA may allow neuroblast migration from the ventricular zone into the cortical plate. Various interactions and localizations of isoforms affect myotube morphology and myogenesis. Isoform 6 accelerates muscle differentiation in vitro.

Actin cytoskeleton organization Source: ProtInc
Cellular response to interferon-gamma Source: Ensembl
Epithelial cell morphogenesis Source: Ensembl
Keratinocyte development Source: Ensembl
Signal transduction Source: ProtInc
Skeletal muscle tissue development Source: Ensembl

Isoform 1: Cytoskeleton; Stress fiber; Cell cortex; Z line. In differentiating myotubes, isoform 1, isoform 2 and isoform 3 are localized diffusely throughout the cytoplasm with regions of enrichment at the longitudinal actin stress fiber. In differentiated tubes, isoform 1 is also detected within the Z-lines.
Isoform 2&3: Stress fiber
Isoform 6: Cytoskeleton. Polarized at the periphery of myotubes.

Interaction with FLNA may compensate for dysfunctional FLNA homodimer in the periventricular nodular heterotopia (PVNH) disorder.
Atelosteogenesis 1 (AO1):
A lethal chondrodysplasia characterized by distal hypoplasia of the humeri and femurs, hypoplasia of the mid-thoracic spine, occasionally complete lack of ossification of single hand bones, and the finding in cartilage of multiple degenerated chondrocytes which are encapsulated in fibrous tissue.
Atelosteogenesis 3 (AO3):
A short-limb lethal skeletal dysplasia with vertebral abnormalities, disharmonious skeletal maturation, poorly modeled long bones and joint dislocations. Recurrent respiratory insufficiency and/or infections usually result in early death.
Boomerang dysplasia (BOOMD):
A perinatal lethal osteochondrodysplasia characterized by absence or underossification of the limb bones and vertebrae. Patients manifest dwarfism with short, bowed, rigid limbs and characteristic facies. Boomerang dysplasia is distinguished from atelosteogenesis on the basis of a more severe defect in mineralization, with complete absence of ossification in some limb elements and vertebral segments.
Larsen syndrome (LRS):
An osteochondrodysplasia characterized by large-joint dislocations and characteristic craniofacial abnormalities. The cardinal features of the condition are dislocations of the hip, knee and elbow joints, with equinovarus or equinovalgus foot deformities. Spatula-shaped fingers, most marked in the thumb, are also present. Craniofacial anomalies include hypertelorism, prominence of the forehead, a depressed nasal bridge, and a flattened midface. Cleft palate and short stature are often associated features. Spinal anomalies include scoliosis and cervical kyphosis. Hearing loss is a well-recognized complication.
Spondylocarpotarsal synostosis syndrome (SCT):
Disorder characterized by short stature and vertebral, carpal and tarsal fusions.

ISGylation prevents ability to interact with the upstream activators of the JNK cascade and inhibits IFNA-induced JNK signaling.
Ubiquitination by a SCF-like complex containing ASB2 isoform 1 leads to proteasomal degradation which promotes muscle differentiation.