Shelterin (also called telosome) is a protein complex known to protect telomeres in many eukaryotes from DNA repair mechanisms, as well as regulate telomerase activity. The components of shelterin were gradually identified over the past years (Fig. 1).

In mammalian cells, the . Shelterin : the protein complex that shapes and safeguards human telomeres. Added by telomerase, arrays of TTAGGG repeats specify the ends of .

The shelterin complex is composed of six polypeptides (Box Fig. 1) and assembles through the binding of the double stranded TTAGGG repeats binding proteins TRF(Fig. 2) and TRF(Fig.

3), , which in turn recruit RAP TIN TPPand POT1. Both TRFand TRFare able to impose a restraint on telomerase, thereby . The telomeres that cap the ends of eukaryotic chromosomes serve a dual role in protecting the chromosome ends and in intracellular signaling for regulating cell proliferation. A complex of six telomere-associated proteins has been identified – the telosome or shelterin complex – that is crucial for both the . Shelterin is a six-subunit protein complex that plays crucial roles in telomere length regulation, protection and maintenance. Although several shelterin subunits have been studied in vitro, the biochemical properties of the fully assembled shelterin complex are not well defined.

Here we characterize shelterin using ensemble . What is shelterin and what does it do?

The human shelterin proteins associate with telomeric DNA to confer telomere protection and length regulation. They are thought to form higher-order protein complexes for their functions, but studies of shelterin proteins have been mostly limited to pairs of proteins. Researchers discover that gene therapy with the Shelterin component TRFinhibits many of the detrimental signs of normal aging in the mouse. Telomeric DNA is capped by the six-protein shelterin complex consisting of TRF, TRF RAP TIN POT and TPP( 9).

These proteins play crucial roles both in preventing the DNA damage response at telomeres and in regulating telomere elongation by telomerase ( 1 11). These prominent new interactions are mediated by the Taz1– Shelterin telomere protection complex and include specific chromosome arm regions containing replication origins bound by Taz1. Our findings uncover an unexpected role for Shelterin in mediating genome reorganization in cells undergoing . The telomere end-protection problem is defined by the aggregate of DNA damage signaling and repair pathways that require repression at telomeres. To define the end-protection problem, we removed the whole shelterin complex from mouse telomeres through conditional deletion of TRFand TRFin . Shelterin forms the core complex of telomere proteins and plays critical roles in protecting telomeres against unwanted activation of the DNA damage response and in maintaining telomere length homeostasis.

Although shelterin expression is believed to be ubiquitous for stabilization of . Germ line mutations in shelterin complex genes are associated with familial chronic lymphocytic leukemia. Law, Kevin Litchfiel Sandrine Jayne, Martin J. Dyer, Claire Dearden, George A. Follows, Daniel Catovsky and Richard S. Lung cellular senescence and inflammatory response are the key events in the pathogenesis of chronic obstructive pulmonary disease (COPD) when cigarette smoke (CS) is the main etiological factor.

Telomere dysfunction is induced by either critical shortening or disruption of the shelterin complex, . How Shelterin Protects Mammalian Telomeres. Annual Review of Genetics. Wilhelm Palm and Titia de Lange.