MYO1C

This gene encodes a member of the unconventional myosin protein family, which are actin-based molecular motors. The protein is found in the cytoplasm, and one isoform with a unique N-terminus is also found in the nucleus. The nuclear isoform associates with RNA polymerase I and II and functions in transcription initiation. The mouse ortholog of this protein also functions in intracellular vesicle transport to the plasma membrane. The related gene myosin IE has been referred to as myosin IC in the literature, but it is a distinct locus on chromosome 19.

Full Name

MYOSIN IC

Function

Myosins are actin-based motor molecules with ATPase activity. Unconventional myosins serve in intracellular movements. Their highly divergent tails are presumed to bind to membranous compartments, which would be moved relative to actin filaments. Involved in glucose transporter recycling in response to insulin by regulating movement of intracellular GLUT4-containing vesicles to the plasma membrane. Component of the hair cell's (the sensory cells of the inner ear) adaptation-motor complex. Acts as a mediator of adaptation of mechanoelectrical transduction in stereocilia of vestibular hair cells. Binds phosphoinositides and links the actin cytoskeleton to cellular membranes.

Isoform 3 is involved in regulation of transcription. Associated with transcriptional active ribosomal genes. Appears to cooperate with the WICH chromatin-remodeling complex to facilitate transcription. Necessary for the formation of the first phosphodiester bond during transcription initiation (By similarity).

Biological Process

Actin filament organization Source: GO_Central
Cellular response to interferon-gamma Source: Ensembl
Chromatin remodeling Source: ComplexPortal
mRNA transport Source: UniProtKB-KW
Positive regulation of cell migration Source: UniProtKB
Positive regulation of cell migration by vascular endothelial growth factor signaling pathway Source: UniProtKB
Positive regulation of cellular response to insulin stimulus Source: Ensembl
Positive regulation of histone acetylation Source: ComplexPortal
Positive regulation of protein targeting to membrane Source: UniProtKB
Positive regulation of transcription by RNA polymerase I Source: ComplexPortal
Positive regulation of transcription by RNA polymerase II Source: ComplexPortal
Positive regulation of transcription by RNA polymerase III Source: ComplexPortal
Positive regulation of vascular endothelial growth factor signaling pathway Source: UniProtKB
Protein targeting to membrane Source: UniProtKB
Regulation of bicellular tight junction assembly Source: UniProtKB
Vesicle transport along actin filament Source: GO_Central

Cellular Location

Isoform 1:
Cytoplasm
Nucleus
Note: Colocalizes with RNA polymerase II. Absent from nucleoli and does not colocalize with RNA polymerase I. Translocates to nuclear speckles upon exposure to inhibitors of RNA polymerase II transcription.
Isoform 2:
Plasma membrane
Cell membrane
stereocilium membrane
Cytoplasm
Other locations
ruffle
Cytoplasmic vesicle
Note: Colocalizes with CABP1 and CIB1 at cell margin, membrane ruffles and punctate regions on the cell membrane. Colocalizes in adipocytes with GLUT4 at actin-based membranes. Colocalizes with GLUT4 at insulin-induced ruffles at the cell membrane. Localizes transiently at cell membrane to region known to be enriched in PIP2. Activation of phospholipase C results in its redistribution to the cytoplasm (By similarity).
Isoform 3:
Nucleus
nucleoplasm
nucleolus
nuclear pore complex
Note: Colocalizes with RNA polymerase II in the nucleus. Colocalizes with RNA polymerase I in nucleoli (By similarity). In the nucleolus, is localized predominantly in dense fibrillar component (DFC) and in granular component (GC). Accumulates strongly in DFC and GC during activation of transcription. Colocalizes with transcription sites. Colocalizes in the granular cortex at the periphery of the nucleolus with RPS6. Colocalizes in nucleoplasm with RPS6 and actin that are in contact with RNP particles. Colocalizes with RPS6 at the nuclear pore level.

PTM

Isoform 2 contains a N-acetylmethionine at position 1.