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 | Expression |
|---|---|---|---|---|---|
A-type lamin | LMNA | 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 | LMNB1 | 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 |
LMNB2 | Lamin B2 | The farnesyl group is essential but not sufficient for the peripheral localization of B-type lamins | Membrane-bound in mitosis | ||
(Lamin B3) |