PubMed Journals: J Neurochem

  Source:		PMID: 9453548

    		J Neurochem. 1998 Feb;70(2):540-9.
			Peripherin is tyrosine-phosphorylated at
			its carboxyl-terminal tyrosine.

			Angelastro JM(1), Ho CL, Frappier T, Liem
			RK, Greene LA.

			Author Information
			(1) Department of Pathology and Center for
			Neurobiology and Behavior, College of Physicians
			and Surgeons of Columbia University, New
			York, New York 10032, USA.

			Peripherin is a type III intermediate filament
			present in peripheral and certain CNS neurons.
			We report here that peripherin contains
			a phosphotyrosine residue and, as such,
			is the only identified intermediate filament
			protein known to be modified in this manner.
			Antiserum specific for phosphotyrosine recognizes
			peripherin present in PC12 cells (with or
			without nerve growth factor treatment)
			and in rat sciatic nerve as well as that
			expressed in Sf-9 cells and SW-13 cl. 2
			vim- cells. The identity of peripherin as
			a tyrosine-phosphorylated protein in PC12
			cells was confirmed by immunoprecipitation,
			two-dimensional isoelectric focusing/sodium
			dodecyl sulfate-polyacrylamide gel electrophoresis
			gels, and phosphoamino acid analysis. Unlike
			serine/threonine phosphorylation, tyrosine
			phosphorylation of peripherin is not regulated
			by depolarization or nerve growth factor
			treatment. To identify the site of tyrosine
			phosphorylation, rat peripherin was mutated
			at several tyrosine residues and expressed
			in SW-13 cl. 2 vim- cells. Tyrosine phosphorylation
			was selectively lost only for peripherin
			mutants in which the carboxy-terminal tyrosine (Y474)
			was mutated. Indirect immunofluorescence
			staining indicated that both wild-type peripherin
			and peripherin Y474F form a filamentous
			network in SW-13 cl. 2 vim- cells. This
			indicates that tyrosine phosphorylation
			of the peripherin C-terminal residue is
			not required for assembly and leaves open
			the possibility that this modification serves
			other functions.

			PMID: 9453548 [Indexed for MEDLINE]

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