Structure
Smads proteins contain two conserved domains. The Mad Homology domain 1 (MH1 domain) is at the N-terminal and the Mad Homology domain 2 (MH2 domain) is at the C-terminal. Between them there is a linker region which is full of regulatory sites. The MH1 domain has DNA binding activity while the MH2 domain has transcriptional activity. The linker region contains important regulatory peptide motifs including potential phosphorylation sites for mitogen-activated protein kinases(MAPKs), Erk-family MAP kinases, the Ca2+ /calmodulin-dependent protein kinase II (CamKII) and protein kinase C (PKC). Smad7 do not have the MH1 domain. A proline-tyrosine (PY) motif presents at its linker region enables its interaction with the WW domains of the E3 ubiquitin ligase, the Smad ubiquitination-related factors (Smurf2). It resides predominantly in the nucleus at basal state and translocates to the cytoplasm by TGF-β stimulation.
Read more about this topic: Mothers Against Decapentaplegic Homolog 7
Famous quotes containing the word structure:
“A structure becomes architectural, and not sculptural, when its elements no longer have their justification in nature.”
—Guillaume Apollinaire (1880–1918)
“One theme links together these new proposals for family policy—the idea that the family is exceedingly durable. Changes in structure and function and individual roles are not to be confused with the collapse of the family. Families remain more important in the lives of children than other institutions. Family ties are stronger and more vital than many of us imagine in the perennial atmosphere of crisis surrounding the subject.”
—Joseph Featherstone (20th century)
“The syntactic component of a grammar must specify, for each sentence, a deep structure that determines its semantic interpretation and a surface structure that determines its phonetic interpretation.”
—Noam Chomsky (b. 1928)