HEAT repeat
Protein tandem repeat From Wikipedia, the free encyclopedia
A HEAT repeat is a protein tandem repeat structural motif composed of two alpha helices linked by a short loop. HEAT repeats can form alpha solenoids, a type of solenoid protein domain found in a number of cytoplasmic proteins. The name "HEAT" is an acronym for four proteins in which this repeat structure is found: Huntingtin, elongation factor 3 (EF3), protein phosphatase 2A (PP2A),[3] and the yeast kinase TOR1.[4] HEAT repeats form extended superhelical structures which are often involved in intracellular transport; they are structurally related to armadillo repeats. The nuclear transport protein importin beta contains 19 HEAT repeats.
HEAT repeat | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
![]() An example of an alpha solenoid structure composed of 15 HEAT repeats. The protein phosphatase 2A regulatory subunit is shown with the N-terminus in blue at bottom and the C-terminus in red at top. A single helix-turn-helix motif is shown in the center with the outer helix in pink, the inner helix in green, and the turn in white. From PDB: 2IAE.[1][2] | |||||||||||
Identifiers | |||||||||||
Symbol | HEAT | ||||||||||
Pfam | PF02985 | ||||||||||
InterPro | IPR000357 | ||||||||||
PROSITE | PDOC50077 | ||||||||||
SCOP2 | 1b3u / SCOPe / SUPFAM | ||||||||||
|
Various HEAT repeat proteins and their structures
Summarize
Perspective
Representative examples of HEAT repeat proteins include importin β (also known as karyopherin β) family,[5] regulatory subunits of condensin and cohesin,[6] separase,[7] PIKKs (phosphatidylinositol 3-kinase-related protein kinases) such as ATM (Ataxia telangiectasia mutated) and ATR (Ataxia telangiectasia and Rad3 related),[8][9] and the microtubule-binding protein XMAP215/Dis1/TOG[10] and CLASP.[11] Thus, cellular functions of HEAT repeat proteins are highly variable.
The structure of the following HEAT repeat proteins have been determined so far:
- Protein modification and degradation
- Nucleo-cytoplasmic transport
- Transcriptional regulation
- Translational regulation
- Elongation factor eEF3[27]
- Initiation factor eIF4G[28]
- Aminoacyl tRNA synthetase transfer protein Cex1p[29]
- DNA repair
- DNA-PK (DNA-dependent protein kinase)[30]
- Fanconi anemia responsible protein FANCF (FANCF)[31]
- Damaged DNA-binding protein AlkD (Alkylpurin DNA glycosylase)[32]
- PIKKs chaperone Tel2[33]
- Chromosomal regulation
- Cytoskeletal regulation
- Microtubule-binding protein TOG[50][51]/Stu2[52]
- Cell proliferation regulation
- TOR (target of rapamycin)[53]
- Others
References
External links
Wikiwand - on
Seamless Wikipedia browsing. On steroids.