RGD Reference Report - Differences in type II, IV, V and VI adenylyl cyclase isoform expression between rat preadipocytes and adipocytes. - Rat Genome Database

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Differences in type II, IV, V and VI adenylyl cyclase isoform expression between rat preadipocytes and adipocytes.

Authors: Serazin-Leroy, V  Morot, M  De Mazancourt, P  Giudicelli, Y 
Citation: Serazin-Leroy V, etal., Biochim Biophys Acta. 2001 Nov 26;1550(1):37-51.
RGD ID: 2312641
Pubmed: (View Article at PubMed) PMID:11738086

Adenylyl cyclase catalytic activity is low in preadipocyte membranes when compared to adipocytes. Under conditions promoting inhibition of adipocyte adenylyl cyclase activity by Gpp(NH)p, a stable GTP analog, a paradoxical increase in preadipocyte adenylyl cyclase activity was obtained. In order to explain this contradiction, expression of types II, IV, V and VI adenylyl cyclase isoforms was compared in adipocytes and undifferentiated preadipocytes both by western blots and by a semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) assay. Type II, IV, V and VI mRNAs and proteins were present in both adipocytes and preadipocytes. However, in undifferentiated preadipocytes, expression of type II mRNA and protein were significantly higher whereas expression of type IV, V and VI adenylyl cyclase mRNAs and proteins were significantly weaker than in adipocytes. In late differentiated preadipocytes, the adenylyl cyclase subtype mRNA expression pattern was intermediary between the undifferentiated and the full differentiation states except for type IV which remained weakly expressed. Moreover, one of the representative regulators of G-protein signaling (RGS protein), RGS4, was less expressed in undifferentiated preadipocyte membranes and cytosol extracts, which contrasts with adipocytes where RGS4 is clearly expressed. Thus, the preferential expression of type II adenylyl cyclase (G(betagamma) subunit-stimulated) in preadipocytes might explain why Gpp(NH)p elicits stimulation of adenylyl cyclase under conditions designed to promote inhibition. Conversely, the preferential expression of type V and VI adenylyl cyclases and the slightly higher expression of type IV adenylyl cyclase in adipocytes could contribute to explain the elevated total catalytic activity observed in mature fat cells compared to their precursor cells.

Annotation

Gene Ontology Annotations    

Biological Process

Cellular Component
cytosol  (IDA)
membrane  (IDA)

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Adcy2  (adenylate cyclase 2)
Adcy4  (adenylate cyclase 4)
Adcy5  (adenylate cyclase 5)
Adcy6  (adenylate cyclase 6)
Rgs4  (regulator of G-protein signaling 4)


Additional Information