Korean J Otolaryngol-Head Neck Surg.  1999 Feb;42(2):145-151.

Localization of Phosphoinositide Specific Phospholipase Cbeta Isozymes in Rat Cochlea

• Park C
• Han SH
• Suh HK
• Jung HH
• Hwang SJ
• Jung K
• Lim HH

Abstract

BACKGROUND AND OBJECTIVES: Phosphoinositide specific phospholipase C (PLC) plays a pivotal role in the transmembrane signal transduction pathways by catalyzing the hydrolysis of phosphoinositide 4,5-bisphosphate (PIP2) to yield the intracellular second messengers, diacylglycerol (DG) and inositol 1,4,5-trisphosphate (IP3), in response to the interaction of various ligands with the cell surface receptors. The question arises as to the physiological roles of the phosphoinositide second messenger system in the inner ear. The purpose of this study was to determine whether PLCbeta isozymes are present at the cochlea and what portion of cochlea each PLCbeta isozymes are distributed in. MAERIALS AND METHODS: Two methods, an immunohistochemical staining and western blot for PLCbeta isozymes were used in the rat cochlea. Frozen section and surface preparation were prepared for immunohistochemical staining. The PLCbeta isozymes or proteolytic digests were separated by SDS-polyacrylamide gels and then electrophoretically transferred to nitrocellulose membranes. Rabbit polyclonal antibodies raised against four PLCbeta isozymes were used.
RESULTS
Each PLCbeta isozymes showed differential expressions in the cochlea. PLCbeta1 immunoreactivity was observed in the inner and outer hair cells and the spiral ganglion cells; PLCbeta2 in the stria vascularis and PLCbeta3 mainly in the inner hair cells. PLCbeta4 was not observed in cochlea. In western blots of rat cochlea extracts, the PLCbeta isozymes stained several bands corresponding to the known molecular weight of PLCbeta monomers, which are probably proteolytic digests.
CONCLUSION
These results suggest that differentially localized each PLCbeta isozymes in the cochlea may have specific roles in signal transduction pathway of auditory system.

Keyword

Phospholipase C beta; Cochlea

MeSH Terms

Animals
Antibodies
Blotting, Western
Cochlea*
Collodion
Ear, Inner
Frozen Sections
Gels
Hair
Hydrolysis
Inositol 1,4,5-Trisphosphate
Isoenzymes*
Ligands
Membranes
Molecular Weight
Phospholipase C beta
Phospholipases*
Rats*
Receptors, Cell Surface
Second Messenger Systems
Signal Transduction
Spiral Ganglion
Stria Vascularis
Type C Phospholipases
Antibodies
Collodion
Gels
Inositol 1,4,5-Trisphosphate
Isoenzymes
Ligands
Phospholipase C beta
Phospholipases
Receptors, Cell Surface
Type C Phospholipases