SUMOylation of nuclear actin

Poly(A) polymerase (PAP) contains regions of similarity with several known protein domains. Through site-directed mutagenesis, we provide evidence that PAP contains a functional ribonucleoprotein-type RNA binding domain (RBD) that is responsible for primer binding, making it the only known polymerase to contain such a domain. The RBD is adjacent to, and probably overlaps with, an apparent catalytic region responsible for polymerization. Despite the presence of sequence similarities, this catalytic domain appears to be distinct from the conserved polymerase module found in a large number of RNA-dependent polymerases. PAP contains two nuclear localization signals (NLSs) in its C terminus, each by itself similar to the consensus bipartite NLS found in many nuclear proteins. Mutagenesis experiments indicate that both signals, which are separated by nearly 140 residues, play important roles in directing PAP exclusively to the nucleus. Surprisingly, basic amino acids in the N-terminal-most NLS are also essential for AAUAAA-dependent polyadenylation but not for nonspecific poly(A) synthesis, suggesting that this region of PAP is involved in interactions both with nuclear targeting proteins and with nuclear polyadenylation factors. The serine/threonine-rich C terminus is multiply phosphorylated, including at sites affected by mutations in either NLS.

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Structural and functional characterization of human microsomal prostaglandin E synthase-1 by computational modeling and site-directed mutagenesis

Bioorganic & Medicinal Chemistry ◽

10.1016/j.bmc.2006.01.010 ◽

2006 ◽

Vol 14 (10) ◽

pp. 3553-3562 ◽

Cited By ~ 24

Author(s):

Xiaoqin Huang ◽

Weili Yan ◽

Daquan Gao ◽

Min Tong ◽

Hsin-Hsiung Tai ◽

...

Keyword(s):

Computational Modeling ◽

Functional Characterization ◽

Site Directed Mutagenesis ◽

Prostaglandin E ◽

Directed Mutagenesis ◽

Prostaglandin E Synthase ◽

Microsomal Prostaglandin E Synthase

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Poly(A) polymerase contains multiple functional domains

Molecular and Cellular Biology ◽

10.1128/mcb.14.5.2946-2957.1994 ◽

1994 ◽

Vol 14 (5) ◽

pp. 2946-2957

Author(s):

T Raabe ◽

K G Murthy ◽

J L Manley

Keyword(s):

Nuclear Localization ◽

Rna Binding ◽

Catalytic Domain ◽

Site Directed Mutagenesis ◽

Nuclear Proteins ◽

Directed Mutagenesis ◽

Nuclear Targeting ◽

Nuclear Localization Signals ◽

C Terminus ◽

Sequence Similarities

Poly(A) polymerase (PAP) contains regions of similarity with several known protein domains. Through site-directed mutagenesis, we provide evidence that PAP contains a functional ribonucleoprotein-type RNA binding domain (RBD) that is responsible for primer binding, making it the only known polymerase to contain such a domain. The RBD is adjacent to, and probably overlaps with, an apparent catalytic region responsible for polymerization. Despite the presence of sequence similarities, this catalytic domain appears to be distinct from the conserved polymerase module found in a large number of RNA-dependent polymerases. PAP contains two nuclear localization signals (NLSs) in its C terminus, each by itself similar to the consensus bipartite NLS found in many nuclear proteins. Mutagenesis experiments indicate that both signals, which are separated by nearly 140 residues, play important roles in directing PAP exclusively to the nucleus. Surprisingly, basic amino acids in the N-terminal-most NLS are also essential for AAUAAA-dependent polyadenylation but not for nonspecific poly(A) synthesis, suggesting that this region of PAP is involved in interactions both with nuclear targeting proteins and with nuclear polyadenylation factors. The serine/threonine-rich C terminus is multiply phosphorylated, including at sites affected by mutations in either NLS.

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