Sains Malaysiana 29: 1-9 (2000)                                                                                                     Sains Hayat /

Life Sciences

Penglibatan Protein Fosfotirosin dalam

Infeksi Plasmodium Berghei

(Involvement of Phosphotyrosine-Containing Protein in

Plasmodium berghei Infection)

Hasidah Mohd Sidek, Chee Suan Kim & Rohani Abd. Kadir

Pusat Pengajian BioSains dan Bioteknologi

Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia

43600 UKM Bangi Selangor D.E, Malaysia

ABSTRACT

The process of phosphorylation-dephosphorylation including those mediated by tyrosine kinase signaling pathway has been reported to influence the process of host invasion by malarial parasite. This study was carried out to assess the relationship between Plasmodium berghei infection and the eryth­rocyte level of phosphotyrosine-containing proteins in mice. Coomassie blue staining of SDS-PAGE gel indicated the presence of several erythrocyte protein bands between 14.4kDa and 97.4kDa in size in the experimental mice. Western blotting [primary antibody = anti-phosphotyrosine; secondary anti­body = anti-IgG mouse conjugate with HRP] failed to show the presence of phosphotyrosine-immunoreactive proteins. Dot blotting however showed the presence of immunoreactive proteins in mice infected with Plasmodium berghei. The immunoreactive proteins were absent in non-infected mice. Densitometric analysis of these immunoreactive proteins indicated that the relative level of phosphotyrosine-containing proteins increased with infection reaching a maximum on day 12 post-infection parallel to a maximum in the level of parasitemia. Data from this study suggests the involvement of tyrosine phosphorylation in Plasmodium berghei infection. 

ABSTRAK 

Kemasukan parasit malaria ke dalam sel perumah dipengaruhi proses pemfosfatan-nyahfosfatan termasuk yang diperantara tapak jalan pengisyaratan tirosin kinase. Kajian ini bertujuan untuk melihat hubungkait antara infeksi Plasmodium berghei dan aras protein fosfotirosin eritrosit mencit. Pewarnaan Coomassie biru gel hasil elektroforesis menunjukkan kehadiran beberapa jalur protein berberat molekul antara 14.4kDa dan 97.4kDa dalam eritrosit mencit kajian. Pemblotan Western [antibodi primer = antilosfotirosin; antibodi sekunder = anti-1gG tikus berkonjugat HRP] gagal mengesan kehadiran jalur protein imunoreaktif-fosfotirosin. Bagaimanapun, pemblotan titik terhadap protein eritrosit (140 μg) mencit terinfeksi menunjukkan kehadiran titik imunoreaktif-fosfotirosin. Titik imunoreaktif ini tidak dikesan dalam protein eritrosit mencit tanpa infeksi. Keamatan protein imunoreaktif yang dicerap dengan densitometer menunjukkan peningkatan aras relatif protein fosfotirosin bersandar tempoh infeksi dan mencapai maksimum pada hari ke 12 selari dengan aras peningkatan parasitemia. Hasil kajian ini mencadangkan wujudnya penglibatan pemfosfatan tirosin dalam infeksi P. berghei.

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