Tubby protein

Tubby Protein
A tubby protein expressed in mouse brain
Identifiers
Symbol	Tub
Pfam	PF01167
InterPro	IPR000007
PROSITE	PDOC00923
SCOP	1c8z
SUPERFAMILY	1c8z
OPM superfamily	177
OPM protein	1i7e
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The tubby protein is encoded by the TUB gene. It is an upstream cell signaling protein common to multicellular eukaryotes. The first tubby gene was identified in mice, and proteins that are homologous to tubby are known as "tubby-like proteins" (TULPs). They share a common and characteristic tertiary structure that consists of a beta barrel packed around an alpha helix in the central pore. The gene derives its name from its role in metabolism; mice with a mutated tubby gene develop delayed-onset obesity, sensorineural hearing loss and retinal degeneration.

Structure

Tubby proteins are classified as α+β proteins and have a 12-beta stranded barrel surrounding a central alpha helix. Tubby proteins can bind the small cell signaling molecule phosphatidylinositol, which is typically localized to the cell membrane. A similar structural fold to the Tubby like proteins has been identified in the Scramblase family of proteins.

Function

Tubby proteins have been implicated as transcription factors and as potential signaling factors coupled to G-protein activity. They are associated with neuronal differentiation and development, and in mammals are implicated in three disease processes when mutated: obesity, retinal degeneration, and hearing loss. In mice, mutations in tubby proteins are known to affect life span and fat storage as well as carbohydrate metabolism. Tubby domains associate with cytoplasmic side of cell membranes through binding of different phosphoinositides

Human proteins containing this domain

TUB; TULP1; TULP2; TULP3; TULP4;

External links

• SCOP tubby fold