TY - JOUR
T1 - mRNA encoding four isoforms of the plasma membrane calcium pump and their variants in rat kidney and nephron segments
AU - Caride, Ariel J.
AU - Chini, Eduardo N.
AU - Homma, Sumiko
AU - Penniston, John T.
AU - Dousa, Thomas P.
PY - 1998/8
Y1 - 1998/8
N2 - To survey the presence of the four different isoforms of the plasma membrane calcium pump (PMCA) and their alternative splicing variants in the rat kidney, three major zones (cortex, outer medulla, and inner medulla) were macrodissected and probed for the presence of mRNA encoding these isoforms and their variants at the splicing site C by using reverse transcription-polymerase Chain reaction (RT-PCR). Both the cortex and the outer medulla showed PMCA 1b, 2b, 3(a and c), and 4b. Semiquantitative comparisons indicated that isoform 2b is more abundant in the cortex than in the outer medulla and conversely, that isoform 3 (a and c) is more abundant in the outer medulla than in the cortex. The inner medulla showed only mRNA for isoforms 1b and 4b. The nephron segments present in the cortex and outer medulla were microdissected and analyzed by RT-PCR. Isoforms 1b, 2b, and 4b were found in all nephron segments but were found more frequently in tubular segments with high rates of Ca2+ reabsorption, suggesting that these isoforms may be involved in transepithelial transport. On the other hand, mRNA encoding isoform 3 (a and c) was most abundant in descending thin limb of Henle but was detected also in glomeruli and cortical thin ascending limb. Its distinct localization suggests that this isoform might have another function, such as in intracellular signalling.
AB - To survey the presence of the four different isoforms of the plasma membrane calcium pump (PMCA) and their alternative splicing variants in the rat kidney, three major zones (cortex, outer medulla, and inner medulla) were macrodissected and probed for the presence of mRNA encoding these isoforms and their variants at the splicing site C by using reverse transcription-polymerase Chain reaction (RT-PCR). Both the cortex and the outer medulla showed PMCA 1b, 2b, 3(a and c), and 4b. Semiquantitative comparisons indicated that isoform 2b is more abundant in the cortex than in the outer medulla and conversely, that isoform 3 (a and c) is more abundant in the outer medulla than in the cortex. The inner medulla showed only mRNA for isoforms 1b and 4b. The nephron segments present in the cortex and outer medulla were microdissected and analyzed by RT-PCR. Isoforms 1b, 2b, and 4b were found in all nephron segments but were found more frequently in tubular segments with high rates of Ca2+ reabsorption, suggesting that these isoforms may be involved in transepithelial transport. On the other hand, mRNA encoding isoform 3 (a and c) was most abundant in descending thin limb of Henle but was detected also in glomeruli and cortical thin ascending limb. Its distinct localization suggests that this isoform might have another function, such as in intracellular signalling.
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U2 - 10.1016/S0022-2143(98)90010-5
DO - 10.1016/S0022-2143(98)90010-5
M3 - Article
C2 - 9708576
AN - SCOPUS:0032145207
VL - 132
SP - 149
EP - 156
JO - Translational Research
JF - Translational Research
SN - 1931-5244
IS - 2
ER -