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Table 1 The basic characteristics of the lamins

From: Chromatin states and nuclear organization in development — a view from the nuclear lamina

Lamin type

Genes (in mammalsa)

Major isoforms/(minor isoforms)

Processing of the C-terminus

Isoelectric point (pK) and solubility in mitosis


A-type lamin


Lamin A

Lamin A and AΔ10 have a CaaX motif that is farnesylated and ultimately cleaved with an additional 15 residues from the C-terminus

pK neutral

Lamins A and C are expressed in most somatic differentiated cells Lamin C2 is expressed in germ cells

Lamin C

Lamin C and C2 have no CaaX motif

Soluble during mitosis

(Lamin AΔ10 Lamin C2)

B-type lamin


Lamin B1

B-type lamins have a CaaX motif that is farnesylated and carboxymethylated on the cysteine, whereas the (aaX) part of the motif is removed

pK acidic

Lamins B1 and B2 are expressed in most or all somatic cells, but lamin B1 is notably absent from muscle cells. Lamin B3 is found in germ cells


Lamin B2

The farnesyl group is essential but not sufficient for the peripheral localization of B-type lamins

Membrane-bound in mitosis

(Lamin B3)

  1. aThe worm Caenorhabditis elegans has a single lamin gene (lmn-1) encoding a protein that has features of both A-type and B-type lamins