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General Comment |
Calcitonin acts through a 7-transmembrane domain, G protein-coupled
receptor (CALCR). Another 7-transmembrane domain receptor, CGRPR , which is 55% identical to
CALCR, had been shown to act as a receptor for the CGRPs only in a single cell line. Receptor
activity-modifying protein-1 (RAMP1), however, transports CGRPR to the cell surface and presents it as a mature
glycoprotein and as a receptor for CGRP. By searching EST databases for sequences related to RAMP1 , followed
by screening a neuroblastoma cDNA library, McLatchie et al. (1998) isolated a cDNA encoding RAMP2. RAMP1, RAMP2,
and RAMP3 share 31% amino acid identity and 56% amino acid similarity.
NCBI Summary:
The protein encoded by this gene is a member of the RAMP family of single-transmembrane-domain proteins, called receptor (calcitonin) activity modifying proteins (RAMPs). RAMPs are type I transmembrane proteins with an extracellular N terminus and a cytoplasmic C terminus. RAMPs are required to transport calcitonin-receptor-like receptor (CRLR) to the plasma membrane. CRLR, a receptor with seven transmembrane domains, can function as either a calcitonin-gene-related peptide (CGRP) receptor or an adrenomedullin receptor, depending on which members of the RAMP family are expressed. In the presence of this (RAMP2) protein, CRLR functions as an adrenomedullin receptor. The RAMP2 protein is involved in core glycosylation and transportation of adrenomedullin receptor to the cell surface.
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Comment |
Transcriptome Comparisons Identify New Cell Markers for Theca Interna and Granulosa Cells from Small and Large Antral Ovarian Follicles. [Hatzirodos N et al. (2015)$25775029] In studies using isolated ovarian granulosa and thecal cells it is important to assess the degree of cross contamination. Marker genes commonly used for granulosa cells include FSHR, CYP19A1 and AMH while CYP17A1 and INSL3 are used for thecal cells. To increase the number of marker genes available we compared expression microarray data from isolated theca interna with that from granulosa cells of bovine small (n = 10 for both theca and granulosa cells; 3-5 mm) and large (n = 4 for both theca and granulosa cells, > 9 mm) antral follicles. Validation was conducted by qRT-PCR analyses. Known markers such as CYP19A1, FSHR and NR5A2 and another 11 genes (LOC404103, MGARP, GLDC, CHST8, CSN2, GPX3, SLC35G1, CA8, CLGN, FAM78A, SLC16A3) were common to the lists of the 50 most up regulated genes in granulosa cells from both follicle sizes. The expression in theca interna was more consistent than in granulosa cells between the two follicle sizes. Many genes up regulated in theca interna were common to both sizes of follicles (MGP, DCN, ASPN, ALDH1A1, COL1A2, FN1, COL3A1, OGN, APOD, COL5A2, IGF2, NID1, LHFP, ACTA2, DUSP12, ACTG2, SPARCL1, FILIP1L, EGFLAM, ADAMDEC1, HPGD, COL12A1, FBLN5, RAMP2, COL15A1, PLK2, COL6A3, LOXL1, RARRES1, FLI1, LAMA2). Many of these were stromal extracellular matrix genes. MGARP, GLDC, CHST8, GPX3 were identified as new potential markers for granulosa cells, while FBLN5, OGN, RAMP2 were significantly elevated in the theca interna.//////////////////
Abe K, et al 2000 reported the expression of adrenomedullin (AM) in the human corpus luteum.
Northern blot analysis of AM, receptor
activity-modifying protein 2 (RAMP2), and LH/hCG receptor mRNA in human
samples.
An AM mRNA transcript of 1.6 kilobases (kb) was detected in corpus
luteum tissue; this transcript was identical to that which has been detected
in placenta and fetal membrane. The AM and LH/hCG receptor mRNA levels were
low in the mature follicle but increased in the corpus luteum of the
mid-luteal phase and were maintained during early pregnancy. A single
transcript of 0.8 kb for RAMP2 was also seen in the follicle and corpus
luteum, the level of RAMP2 mRNA was relatively high in the preovulatory
follicle and RAMP2 was present in the corpus luteum.
In conclusion, the expression of AM, its receptor, and LH/hCG receptor may be
an important component in the process of development and differentiation of
the corpus luteum.
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