Lamin B2 is a protein that in humans is encoded by the LMNB2 gene. It is the second of two type B nuclear lamins, and it is associated with laminopathies. The LMNB2 gene also codes for the testis-specific transcript, Lamin B3 generated by alternative splicing. Relative to its other isoforms, lamin B2 is the least abundant lamin in the nuclei of somatic cells. Like all lamins, its structure is composed of an α-helical central rod domain with a N-terminal globular head domain and a C-terminal tail.
Function Lamin B2 along with its isoforms comprise the nuclear matrix that is responsible for maintaining nucleus shape and the organization of chromatin. B2 has been shown to form mesh-like structures with other lamins along the nuclear envelope. These meshworks associate with LINC complexes, inner nuclear membrane proteins and underlying chromatin. In addition to its localization along the nuclear envelope, B2 also plays a role in regulating nucleolar morphology. It associates with nucleolin and nucleophosmin and localizes to the granular component of nucleoli. It has been shown to regulate expression of the 45S rRNA.
Neurodevelopment Lamin B2 is also a necessary factor in nuclear translocation, an important step in neuronal migration during embryonic development of the cerebral cortex. However, the role of B2 in the process has not yet been characterized as it is not an interactor of the LINC complex.
See also Lamin B receptor Barraquer–Simons syndrome Pelger–Huët anomaly
References
External links Lamin+B at the U.S. National Library of Medicine Medical Subject Headings (MeSH)