Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: On the assumption that depho~phoryiation of the n~urotropic.coronavirus J HM (JHMV) nuclcocap~ld protein (NI may be connected with initiation or the infectiaas cycle we ~arehed for a relevant host enxyme activity, Analysi~ of ~ubccllular fractions from L-2 murin© flhrt~bla~ts, ~parate¢l t ~ dual Percoll density g, tadieats, revealed the presence of a pho~phoprotei~ phosphatase (PPPaseL co.~cdimcntinll with the endososomai/prelyso. s~im.I material, which possesses high activity alainxt N, With purified pZPJN as substratc it was demonstrated that this PPPase. d stinilaishable from acid and tdkalin~ phosph~tascs, acts optimalb, at neutral pl'{ in th© pres©nc¢ of Mn ]" following treatment with a detergent, Complete inhibition wi:h okadaic acid at 0.9.-4,$ tIM but not at b, d0 nM relegates thi~ PPPasc ton type I protein phosphatase. Similar PPPase activily for N was present in the endosome fraction of at rat Roc. 1 astrocytoma.olijlodendroc~cte cell line and in homc~lenates of brain and cultured OliltOdendrocytes. Oar d~ta sul/gest that the phosphorylatcd N of the inoculum may be modified by the endosomal PPPa~e in hosl ¢©11~, incladinil tho~c from the CNS so a~ to factlitale the .II.IMV infectious process. In this paper, we present data regarding partial characterization of a phosphoprotein phosphatase, associated with the endosomal fraction of host cells (PPPase), which is highly active against the nucleocapsid protein IN) of JHMV. Among the 3 major structural proteins of JHMV, N is phosphorylated [91 and has the capacity to bind nucleic acid [10]. Implications of dephosphorylation of N on early host-virus interactions are discussed. EXPERIMENTAL Okadaic acid was purchased from Monna Bioproducts0 Hawaii. Acid phosphatase of potato was obtained from Nutritional Bioclaemical Corporation, Ohio, alkaline phosphatase of E. colt from Sigma, St, Louis and Percoll from Pharnaacia, Propagation of L-2 murine fibroblasts [11] as monolayers and coronavirus JHMV, including plaque assays (pfu), followed procedures described previously [5] , Susper~sior, cultures of L-2 cells for biochemical studies were grown in MEM supplemented with 8% Nu-Serum plus 2% FBS, The immortalized Roe.1 cell-cell hybrid fine, of rat C~ glioma x primary oligodendrocyte (a kind gift from Dr. F.A, McMorris, The Wistar Institute, Philadelphia, PAl, was grown in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10070 FBS, 1.2 g/l NaHCOa and I xHAT supplement (Gibco), Primary cultures enriched for rat oligodendrocytes (95a70 pure) were isolated and cultured for 10 days as described previously [12] . Homogenates obtained by a Dounce homogeniser of oligodendrocyte and whole brain from 2-day-old rats were suspended in Published by Elsevier Science Publishers B. V.

Endosomal association of a protein phosphatase with high dephosphorylating activity against a coronavirus nucleocapsid protein