Family

Intermediate filament protein (IPR001664)

Short name: IF

Family relationships

Description

Intermediate filaments (IF) [PMID: 8771189, PMID: 3052284, PMID: 2183847] are proteins which are primordial components of the cytoskeleton and the nuclear envelope. They generally form filamentous structures 8 to 14 nm wide.

IF proteins are members of a very large multigene family of proteins which has been subdivided in five major subgroups:

  • Type I: Acidic cytokeratins.
  • Type II: Basic cytokeratins.
  • Type III: Vimentin, desmin, glial fibrillary acidic protein (GFAP), peripherin, and plasticin.
  • Type IV: Neurofilaments L, H and M, alpha-internexin and nestin.
  • Type V: Nuclear lamins A, B1, B2 and C.
  • Type VI: Nestin.

All IF proteins are structurally similar in that they consist of: a central rod domain comprising some 300 to 350 residues which is arranged in coiled-coiled alpha-helices, with at least two short characteristic interruptions; a N-terminal non-helical domain (head) of variable length; and a C-terminal domain (tail) which is also non-helical, and which shows extreme length variation between different IF proteins.

While IF proteins are evolutionary and structurally related, they have limited sequence homologies except in several regions of the rod domain.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005198 structural molecule activity

Cellular Component

GO:0005882 intermediate filament

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
Pfam
PANTHER