Hemidesmosomes are structures which link the basal lamina to the intermediate filament cytoskeleton. An important functional component of hemidesmosomes is the integrin beta-4 subunit (ITGB4), a protein containing two fibronectin type III domains. The protein encoded by Intergrin beta 4 binding protein binds to the fibronectin type III domains of ITGB4 and may help link ITGB4 to the intermediate filament cytoskeleton. The encoded protein, which is insoluble and found both in the nucleus and in the cytoplasm, can function as a translation initiation factor and prevent the association of the 40S and 60S ribosomal subunits. Multiple transcript variants encoding several different isoforms have been found for this gene.
Function:
Binds to the 60S ribosomal subunit and prevents its association with the 40S ribosomal subunit to form the 80S initiation complex in the cytoplasm. May behave as a stimulatory translation initiation factor downstream insulin/growth factors. Is also involved in ribosome biogenesis. Associates with pre-60S subunits in the nucleus and is involved in its nuclear export. Cytoplasmic release of TIF6 from 60S subunits and nuclear relocalization is promoted by a RACK1 (GNB2L1)-dependent protein kinase C activity.
Subunit:
Belongs to the eIF-6 family.
Subcellular Location:
Cytoplasm. Nucleus. nucleolus. Shuttles between cytoplasm and nucleus/nucleolus.
Tissue Specificity:
Expressed at very high levels in colon carcinoma with lower levels in normal colon and ileum and lowest levels in kidney and muscle (at protein level).
Post-translational modifications:
Phosphorylation at Ser-174 and Ser-175 by CSNK1D/CK1 promotes nuclear export.
Similarity:
Belongs to the eIF-6 family.
SWISS:
P56537
Gene ID:
3692
Database links:
Entrez Gene: 3692 Human
Entrez Gene: 16418 Mouse
Entrez Gene: 305506 Rat
Omim: 602912 Human
SwissProt: P56537 Human
SwissProt: O55135 Mouse
SwissProt: Q3KRD8 Rat
Unigene: 654848 Human
Unigene: 271674 Mouse
Unigene: 190833 Rat
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