|
KMID : 0811720050090000071
|
|
Korean Journal of Physiology & Pharmacology
2005 Volume.9 No. 0 p.71 ~ p.0
|
|
|
Role of the Homer2 in Calcium Signaling in Parotid Acinar Cells
|
|
Kim Seung-Hyeoi
Jo Hae
Lee Syng-Ill
Shin Dong-Min
|
|
|
Abstract
|
|
|
The Homer protein, a scaffolding protein, has 3 isoforms: Homer1, Homer2, and Homer3. The Homer protein has EVH1/WH1 domain, which specifically recognizes PPXXF sequence (P: proline, X: any amino acid). This sequence specific to the Homer protein is known to adhere with group 1 metabotropic glutamate (mGlu) receptor, IP3 receptor, and ryanodine receptor among other proteins that are related to calcium signaling. Furthermore, the Homer protein plays a role in the formation of synapses in neuronal cells and in targeting of mGlu receptors. However, the role of the Homer protein in calcium signaling in non-neuronal cells is not known. The present study examined the role of the Homer protein in calcium signaling in parotid acinar cells of Homer2 knockout mice. The expression of IP3 receptors increased in Homer 2-/- parotid cells and this was interpreted as the Homer protein not only targeting the IP3 receptor but also as regulated the amount of expression. However, in the in vivo study, there was no difference noted in the level of activity of IP3 between the control group and the Homer 2-/- parotid cells. Whereas SERCA activity and expression levels were similar in both groups of mice, PMCA expression levels and its activity were up-regulated. The peptide sequencing of PMCA 1～4 isotype showed a proline-rich sequence of PPXXF at the N-terminal of all of PMCA isotypes. Using the antibodies of PMCA, co-immunoprecipitation results showed that the Homer protein and PMCA were participating in protein-protein interaction. Thses results suggested that the in parotid acinar cells protein-protein interaction between the Homer protein and PMCA regulate the expression and activity of PMCA.
Source: Korean Journal of Physiology & Pharmacology.2005 Oct;9(Suppl I):S91-S91
|
|
|
KEYWORD
|
|
|
Homer protein, Calcium signaling, Homer2 knockout mice, PMCA
|
|
|
FullTexts / Linksout information
|
|
|
|
|
Listed journal information
|
|
  
|
|